Agreement/Disagreement
See Also: COMPATIBILITY, FIGHTING
1. About as far apart as an atheist and a born-again Christian —Anon
2. Acquiesced like an old man acquiescing in death —Wilfrid Sheed
3. (Nobody can be as) agreeable as an uninvited guest —Frank McKinney
Humorists like McKinney are notable phrase converters. This simile may be a case in point, evolving from William Wordsworth’s sonnet To a Snowdrop which describes a flower bending its forehead “As if fearful to offend, like an unbidden guest.”
See Also: BEHAVIOR
4. Agree like a finger and a thumb —Anon
5. Agree like two cats in a gutter —John Heywood’s Proverbs
6. Agree like cats and dogs —John Ray’s Proverbs
This sarcastic twist to the more commonly used “Fight like cats and dogs” dates back to the nineteenth century.
7. Agree like pickpockets in a fair —John Ray’s Proverbs
8. Agree like the clocks of London —Richard Brinsley Sheridan
9. As coals are to burning coals, and wood to fire, so is a contentious man to kindle strife —The Holy Bible/Proverbs
10. As far apart as the atheists who claim there is no soul, and the Christian Scientists who declare there is no body —Anon
11. Co-operate about as much as two tomcats on a fence —Raymond Chandler
12. Far apart as the poles —Anon
13. Flock together in consent, like so many wild geese —William Shakespeare
14. Like the course of the heavenly bodies, harmony in national life is a resultant of the struggle between contending forces —Judge Louis D. Brandeis
15. Sentiments as equal as if weighed on a golden scale —Janet Flanner
16. We are made for cooperation, like feet, like hands, like eyelids, like the row of the upper and lower teeth. To act against one another is contrary to nature —Marcus Aurelius
Kamis, 17 Februari 2011
Agreement
Subject-Verb
Agreement
#
PowerpointIf your computer is equipped with PowerPoint, click on the PowerPoint icon to the right for a brief PowerPoint presentation on Subject-Verb Agreement.
Click HERE for help with Powerpoint.
Basic Principle: Singular subjects need singular verbs; plural subjects need plural verbs. My brother is a nutritionist. My sisters are mathematicians.
See the section on Plurals for additional help with subject-verb agreement.
1
The indefinite pronouns anyone, everyone, someone, no one, nobody are always singular and, therefore, require singular verbs.
* Everyone has done his or her homework.
* Somebody has left her purse.
Some indefinite pronouns — such as all, some — are singular or plural depending on what they're referring to. (Is the thing referred to countable or not?) Be careful choosing a verb to accompany such pronouns.
* Some of the beads are missing.
* Some of the water is gone.
On the other hand, there is one indefinite pronoun, none, that can be either singular or plural; it often doesn't matter whether you use a singular or a plural verb — unless something else in the sentence determines its number. (Writers generally think of none as meaning not any and will choose a plural verb, as in "None of the engines are working," but when something else makes us regard none as meaning not one, we want a singular verb, as in "None of the food is fresh.")
* None of you claims responsibility for this incident?
* None of you claim responsibility for this incident?
* None of the students have done their homework. (In this last example, the word their precludes the use of the singular verb.
2
Some indefinite pronouns are particularly troublesome Everyone and everybody (listed above, also) certainly feel like more than one person and, therefore, students are sometimes tempted to use a plural verb with them. They are always singular, though. Each is often followed by a prepositional phrase ending in a plural word (Each of the cars), thus confusing the verb choice. Each, too, is always singular and requires a singular verb.
Everyone has finished his or her homework.
You would always say, "Everybody is here." This means that the word is singular and nothing will change that.
Each of the students is responsible for doing his or her work in the library.
Don't let the word "students" confuse you; the subject is each and each is always singular — Each is responsible.
3
Phrases such as together with, as well as, and along with are not the same as and. The phrase introduced by as well as or along with will modify the earlier word (mayor in this case), but it does not compound the subjects (as the word and would do).
* The mayor as well as his brothers is going to prison.
* The mayor and his brothers are going to jail.
4
The pronouns neither and either are singular and require singular verbs even though they seem to be referring, in a sense, to two things.
* Neither of the two traffic lights is working.
* Which shirt do you want for Christmas?
Either is fine with me.
In informal writing, neither and either sometimes take a plural verb when these pronouns are followed by a prepositional phrase beginning with of. This is particularly true of interrogative constructions: "Have either of you two clowns read the assignment?" "Are either of you taking this seriously?" Burchfield calls this "a clash between notional and actual agreement."*
5
The conjunction or does not conjoin (as and does): when nor or or is used the subject closer to the verb determines the number of the verb. Whether the subject comes before or after the verb doesn't matter; the proximity determines the number.
* Either my father or my brothers are going to sell the house.
* Neither my brothers nor my father is going to sell the house.
* Are either my brothers or my father responsible?
* Is either my father or my brothers responsible?
Because a sentence like "Neither my brothers nor my father is going to sell the house" sounds peculiar, it is probably a good idea to put the plural subject closer to the verb whenever that is possible.
6
The words there and here are never subjects.
* There are two reasons [plural subject] for this.
* There is no reason for this.
* Here are two apples.
With these constructions (called expletive constructions), the subject follows the verb but still determines the number of the verb.
7
Verbs in the present tense for third-person, singular subjects (he, she, it and anything those words can stand for) have s-endings. Other verbs do not add s-endings.
He loves and she loves and they love_ and . . . .
8
Sometimes modifiers will get betwen a subject and its verb, but these modifiers must not confuse the agreement between the subject and its verb.
The mayor, who has been convicted along with his four brothers on four counts of various crimes but who also seems, like a cat, to have several political lives, is finally going to jail.
9
Sometimes nouns take weird forms and can fool us into thinking they're plural when they're really singular and vice-versa. Consult the section on the Plural Forms of Nouns and the section on Collective Nouns for additional help. Words such as glasses, pants, pliers, and scissors are regarded as plural (and require plural verbs) unless they're preceded the phrase pair of (in which case the word pair becomes the subject).
* My glasses were on the bed.
* My pants were torn.
* A pair of plaid trousers is in the closet.
10
Some words end in -s and appear to be plural but are really singular and require singular verbs.
* The news from the front is bad.
* Measles is a dangerous disease for pregnant women.
On the other hand, some words ending in -s refer to a single thing but are nonetheless plural and require a plural verb.
* My assets were wiped out in the depression.
* The average worker's earnings have gone up dramatically.
* Our thanks go to the workers who supported the union.
The names of sports teams that do not end in "s" will take a plural verb: the Miami Heat have been looking … , The Connecticut Sun are hoping that new talent … . See the section on plurals for help with this problem.
11
Fractional expressions such as half of, a part of, a percentage of, a majority of are sometimes singular and sometimes plural, depending on the meaning. (The same is true, of course, when all, any, more, most and some act as subjects.) Sums and products of mathematical processes are expressed as singular and require singular verbs. The expression "more than one" (oddly enough) takes a singular verb: "More than one student has tried this."
* Some of the voters are still angry.
* A large percentage of the older population is voting against her.
* Two-fifths of the troops were lost in the battle.
* Two-fifths of the vineyard was destroyed by fire.
* Forty percent of the students are in favor of changing the policy.
* Forty percent of the student body is in favor of changing the policy.
* Two and two is four.
* Four times four divided by two is eight.
12
If your sentence compounds a positive and a negative subject and one is plural, the other singular, the verb should agree with the positive subject.
* The department members but not the chair have decided not to teach on Valentine's Day.
* It is not the faculty members but the president who decides this issue.
* It was the speaker, not his ideas, that has provoked the students to riot.
For additional help with subject-verb agreement, see Chapter 12 of Sentence Sense: A Writer's Guide.
Agreement
#
PowerpointIf your computer is equipped with PowerPoint, click on the PowerPoint icon to the right for a brief PowerPoint presentation on Subject-Verb Agreement.
Click HERE for help with Powerpoint.
Basic Principle: Singular subjects need singular verbs; plural subjects need plural verbs. My brother is a nutritionist. My sisters are mathematicians.
See the section on Plurals for additional help with subject-verb agreement.
1
The indefinite pronouns anyone, everyone, someone, no one, nobody are always singular and, therefore, require singular verbs.
* Everyone has done his or her homework.
* Somebody has left her purse.
Some indefinite pronouns — such as all, some — are singular or plural depending on what they're referring to. (Is the thing referred to countable or not?) Be careful choosing a verb to accompany such pronouns.
* Some of the beads are missing.
* Some of the water is gone.
On the other hand, there is one indefinite pronoun, none, that can be either singular or plural; it often doesn't matter whether you use a singular or a plural verb — unless something else in the sentence determines its number. (Writers generally think of none as meaning not any and will choose a plural verb, as in "None of the engines are working," but when something else makes us regard none as meaning not one, we want a singular verb, as in "None of the food is fresh.")
* None of you claims responsibility for this incident?
* None of you claim responsibility for this incident?
* None of the students have done their homework. (In this last example, the word their precludes the use of the singular verb.
2
Some indefinite pronouns are particularly troublesome Everyone and everybody (listed above, also) certainly feel like more than one person and, therefore, students are sometimes tempted to use a plural verb with them. They are always singular, though. Each is often followed by a prepositional phrase ending in a plural word (Each of the cars), thus confusing the verb choice. Each, too, is always singular and requires a singular verb.
Everyone has finished his or her homework.
You would always say, "Everybody is here." This means that the word is singular and nothing will change that.
Each of the students is responsible for doing his or her work in the library.
Don't let the word "students" confuse you; the subject is each and each is always singular — Each is responsible.
3
Phrases such as together with, as well as, and along with are not the same as and. The phrase introduced by as well as or along with will modify the earlier word (mayor in this case), but it does not compound the subjects (as the word and would do).
* The mayor as well as his brothers is going to prison.
* The mayor and his brothers are going to jail.
4
The pronouns neither and either are singular and require singular verbs even though they seem to be referring, in a sense, to two things.
* Neither of the two traffic lights is working.
* Which shirt do you want for Christmas?
Either is fine with me.
In informal writing, neither and either sometimes take a plural verb when these pronouns are followed by a prepositional phrase beginning with of. This is particularly true of interrogative constructions: "Have either of you two clowns read the assignment?" "Are either of you taking this seriously?" Burchfield calls this "a clash between notional and actual agreement."*
5
The conjunction or does not conjoin (as and does): when nor or or is used the subject closer to the verb determines the number of the verb. Whether the subject comes before or after the verb doesn't matter; the proximity determines the number.
* Either my father or my brothers are going to sell the house.
* Neither my brothers nor my father is going to sell the house.
* Are either my brothers or my father responsible?
* Is either my father or my brothers responsible?
Because a sentence like "Neither my brothers nor my father is going to sell the house" sounds peculiar, it is probably a good idea to put the plural subject closer to the verb whenever that is possible.
6
The words there and here are never subjects.
* There are two reasons [plural subject] for this.
* There is no reason for this.
* Here are two apples.
With these constructions (called expletive constructions), the subject follows the verb but still determines the number of the verb.
7
Verbs in the present tense for third-person, singular subjects (he, she, it and anything those words can stand for) have s-endings. Other verbs do not add s-endings.
He loves and she loves and they love_ and . . . .
8
Sometimes modifiers will get betwen a subject and its verb, but these modifiers must not confuse the agreement between the subject and its verb.
The mayor, who has been convicted along with his four brothers on four counts of various crimes but who also seems, like a cat, to have several political lives, is finally going to jail.
9
Sometimes nouns take weird forms and can fool us into thinking they're plural when they're really singular and vice-versa. Consult the section on the Plural Forms of Nouns and the section on Collective Nouns for additional help. Words such as glasses, pants, pliers, and scissors are regarded as plural (and require plural verbs) unless they're preceded the phrase pair of (in which case the word pair becomes the subject).
* My glasses were on the bed.
* My pants were torn.
* A pair of plaid trousers is in the closet.
10
Some words end in -s and appear to be plural but are really singular and require singular verbs.
* The news from the front is bad.
* Measles is a dangerous disease for pregnant women.
On the other hand, some words ending in -s refer to a single thing but are nonetheless plural and require a plural verb.
* My assets were wiped out in the depression.
* The average worker's earnings have gone up dramatically.
* Our thanks go to the workers who supported the union.
The names of sports teams that do not end in "s" will take a plural verb: the Miami Heat have been looking … , The Connecticut Sun are hoping that new talent … . See the section on plurals for help with this problem.
11
Fractional expressions such as half of, a part of, a percentage of, a majority of are sometimes singular and sometimes plural, depending on the meaning. (The same is true, of course, when all, any, more, most and some act as subjects.) Sums and products of mathematical processes are expressed as singular and require singular verbs. The expression "more than one" (oddly enough) takes a singular verb: "More than one student has tried this."
* Some of the voters are still angry.
* A large percentage of the older population is voting against her.
* Two-fifths of the troops were lost in the battle.
* Two-fifths of the vineyard was destroyed by fire.
* Forty percent of the students are in favor of changing the policy.
* Forty percent of the student body is in favor of changing the policy.
* Two and two is four.
* Four times four divided by two is eight.
12
If your sentence compounds a positive and a negative subject and one is plural, the other singular, the verb should agree with the positive subject.
* The department members but not the chair have decided not to teach on Valentine's Day.
* It is not the faculty members but the president who decides this issue.
* It was the speaker, not his ideas, that has provoked the students to riot.
For additional help with subject-verb agreement, see Chapter 12 of Sentence Sense: A Writer's Guide.
Expressing Opinions
Expressing Opinions
English Vocabulary
Below are some phrases that you can use to help express opinions. Some of these phrases are more appropriate for written English such as giving your opinion in an essay whereas some can also be used in spoken English.
Personal Point of View
We use these words and phrases to express a personal point of view:
* In my experience…
* As far as I’m concerned…
* Speaking for myself…
* In my opinion…
* Personally, I think…
* I’d say that…
* I’d suggest that…
* I’d like to point out that…
* I believe that…
* What I mean is…
General Point of View
We use these words and phrases to express a point of view that is generally thought by people:
* It is thought that...
* Some people say that...
* It is considered...
* It is generally accepted that...
Agreeing with an opinion
We use these words and phrases to agree with someone else’s point of view:
* Of course.
* You’re absolutely right.
* Yes, I agree.
* I think so too.
* That’s a good point.
* Exactly.
* I don’t think so either.
* So do I.
* I'd go along with that.
* That’s true.
* Neither do I.
* I agree with you entirely.
* That's just what I was thinking.
* I couldn't agree more.
Disagreeing with an opinion
We use these words and phrases to disagree with someone else’s point of view:
* That’s different.
* I don’t agree with you.
* However…
* That’s not entirely true.
* On the contrary…
* I’m sorry to disagree with you, but…
* Yes, but don’t you think…
* That’s not the same thing at all.
* I’m afraid I have to disagree.
* I'm not so sure about that.
* I must take issue with you on that.
* It's unjustifiable to say that...
English Vocabulary
Below are some phrases that you can use to help express opinions. Some of these phrases are more appropriate for written English such as giving your opinion in an essay whereas some can also be used in spoken English.
Personal Point of View
We use these words and phrases to express a personal point of view:
* In my experience…
* As far as I’m concerned…
* Speaking for myself…
* In my opinion…
* Personally, I think…
* I’d say that…
* I’d suggest that…
* I’d like to point out that…
* I believe that…
* What I mean is…
General Point of View
We use these words and phrases to express a point of view that is generally thought by people:
* It is thought that...
* Some people say that...
* It is considered...
* It is generally accepted that...
Agreeing with an opinion
We use these words and phrases to agree with someone else’s point of view:
* Of course.
* You’re absolutely right.
* Yes, I agree.
* I think so too.
* That’s a good point.
* Exactly.
* I don’t think so either.
* So do I.
* I'd go along with that.
* That’s true.
* Neither do I.
* I agree with you entirely.
* That's just what I was thinking.
* I couldn't agree more.
Disagreeing with an opinion
We use these words and phrases to disagree with someone else’s point of view:
* That’s different.
* I don’t agree with you.
* However…
* That’s not entirely true.
* On the contrary…
* I’m sorry to disagree with you, but…
* Yes, but don’t you think…
* That’s not the same thing at all.
* I’m afraid I have to disagree.
* I'm not so sure about that.
* I must take issue with you on that.
* It's unjustifiable to say that...
Rabu, 16 Februari 2011
kesetimbangan kimia
Kesetimbangan kimia
Reaksi yang dapat berlangsung dalam dua arah disebut reaksi dapat balik. Apabila dalam suatu reaksi kimia, kecepatan reaksi ke kanan sama dengan kecepatan reaksi ke kiri maka, reaksi dikatakan dalam keadaan setimbang. Secara umum reaksi kesetimbangan dapat dinyatakan sebagai:
A + B ® C + D
ADA DUA MACAM SISTEM KESETIMBANGAN, YAITU :
1.
Kesetimbangan dalam sistem homogen
a.
Kesetimbangan dalam sistem gas-gas
Contoh: 2SO2(g) + O2(g) « 2SO3(g)
b.
Kesetimbangan dalam sistem larutan-larutan
Contoh: NH4OH(aq) « NH4+(aq) + OH- (aq)
2.
Kesetimbangan dalam sistem heterogen
a.
Kesetimbangan dalam sistem padat gas
Contoh: CaCO3(s) « CaO(s) + CO2(g)
b.
Kesetimbangan sistem padat larutan
Contoh: BaSO4(s) « Ba2+(aq) + SO42- (aq)
c.
Kesetimbangan dalam sistem larutan padat gas
Contoh: Ca(HCO3)2(aq) « CaCO3(s) + H2O(l) + CO2(g)
Hukum Guldberg dan Wange:
Dalam keadaan kesetimbangan pada suhu tetap, maka hasil kali konsentrasi zat-zat hasil reaksi dibagi dengan hasil kali konsentrasi pereaksi yang sisa dimana masing-masing konsentrasi itu dipangkatkan dengan koefisien reaksinya adalah tetap.
Pernyataan tersebut juga dikenal sebagai hukum kesetimbangan.
Untuk reaksi kesetimbangan: a A + b B « c C + d D maka:
Kc = (C)c x (D)d / (A)a x (B)b
Kc adalah konstanta kesetimbangan yang harganya tetap selama suhu tetap.
BEBERAPA HAL YANG HARUS DIPERHATIKAN
-
Jika zat-zat terdapat dalam kesetimbangan berbentuk padat dan gas yang dimasukkan dalam, persamaan kesetimbangan hanya zat-zat yang berbentuk gas saja sebab konsentrasi zat padat adalah tetap den nilainya telah terhitung dalam harga Kc itu.
Contoh: C(s) + CO2(g) « 2CO(g)
Kc = (CO)2 / (CO2)
-
Jika kesetimbangan antara zat padat dan larutan yang dimasukkan dalam perhitungan Kc hanya konsentrasi zat-zat yang larut saja.
Contoh: Zn(s) + Cu2+(aq) « Zn2+(aq) + Cu(s)
Kc = (Zn2+) / (CO2+)
-
Untuk kesetimbangan antara zat-zat dalam larutan jika pelarutnya tergolong salah satu reaktan atau hasil reaksinya maka konsentrasi dari pelarut itu tidak dimasukkan dalam perhitungan Kc.
Contoh: CH3COO-(aq) + H2O(l) « CH3COOH(aq) + OH-(aq)
Kc = (CH3COOH) x (OH-) / (CH3COO-)
Contoh soal:
1. Satu mol AB direaksikan dengan satu mol CD menurut persamaan reaksi:
AB(g) + CD(g) « AD(g) + BC(g)
Setelah kesetimbangan tercapai ternyata 3/4 mol senyawa CD berubah menjadi AD dan BC. Kalau volume ruangan 1 liter, tentukan tetapan kesetimbangan untuk reaksi ini !
Jawab:
Perhatikan reaksi kesetimbangan di atas jika ternyata CD berubah (bereaksi) sebanyak 3/4 mol maka AB yang bereaksi juga 3/4 mol (karena koefsiennya sama).
Dalam keadaan kesetimbangan:
(AD) = (BC) = 3/4 mol/l
(AB) sisa = (CD) sisa = 1 - 3/4 = 1/4 n mol/l
Kc = [(AD) x (BC)]/[(AB) x (CD)] = [(3/4) x (3/4)]/[(1/4) x (1/4)] = 9
2. Jika tetapan kesetimbangan untuk reaksi:
A(g) + 2B(g) « 4C(g)
sama dengan 0.25, maka berapakah besarnya tetapan kesetimbangan bagi reaksi:
2C(g) « 1/2A(g) + B(g)
Jawab:
- Untuk reaksi pertama: K1 = (C)4/[(A) x (B)2] = 0.25
- Untuk reaksi kedua : K2 = [(A)1/2 x (B)]/(C)2
- Hubungan antara K1 dan K2 dapat dinyatakan sebagai:
K1 = 1 / (K2)2 ® K2 = 2
Azas Le Chatelier menyatakan: Bila pada sistem kesetimbangan diadakan aksi, maka sistem akan mengadakan reaksi sedemikian rupa sehingga pengaruh aksi itu menjadi sekecil-kecilnya.
Perubahan dari keadaan kesetimbangan semula ke keadaan kesetimbangan yang baru akibat adanya aksi atau pengaruh dari luar itu dikenal dengan pergeseran kesetimbangan.
Bagi reaksi:
A + B « C + D
KEMUNGKINAN TERJADINYA PERGESERAN
1.
Dari kiri ke kanan, berarti A bereaksi dengan B memhentuk C dan D, sehingga jumlah mol A dan Bherkurang, sedangkan C dan D bertambah.
2.
Dari kanan ke kiri, berarti C dan D bereaksi membentuk A dan B. sehingga jumlah mol C dan Dherkurang, sedangkan A dan B bertambah.
FAKTOR-FAKTOR YANG DAPAT MENGGESER LETAK KESETIMBANGAN ADALAH :
a. Perubahan konsentrasi salah satu zat
b. Perubahan volume atau tekanan
c. Perubahan suhu
A. PERUBAHAN KONSENTRASI SALAH SATU ZAT
Apabila dalam sistem kesetimbangan homogen, konsentrasi salah satu zat diperbesar, maka kesetimbangan akan bergeser ke arah yang berlawanan dari zat tersebut. Sebaliknya, jika konsentrasi salah satu zat diperkecil, maka kesetimbangan akan bergeser ke pihak zat tersebut.
Contoh: 2SO2(g) + O2(g) « 2SO3(g)
- Bila pada sistem kesetimbangan ini ditambahkan gas SO2, maka kesetimbangan akan bergeser ke kanan.
- Bila pada sistem kesetimbangan ini dikurangi gas O2, maka kesetimbangan akan bergeser ke kiri.
B. PERUBAHAN VOLUME ATAU TEKANAN
Jika dalam suatu sistem kesetimbangan dilakukan aksi yang menyebabkan perubahan volume (bersamaan dengan perubahan tekanan), maka dalam sistem akan mengadakan berupa pergeseran kesetimbangan.
Jika tekanan diperbesar = volume diperkecil, kesetimbangan akan bergeser ke arah jumlah Koefisien Reaksi Kecil.
Jika tekanan diperkecil = volume diperbesar, kesetimbangan akan bergeser ke arah jumlah Koefisien reaksi besar.
Pada sistem kesetimbangan dimana jumlah koefisien reaksi sebelah kiri = jumlah koefisien sebelah kanan, maka perubahan tekanan/volume tidak menggeser letak kesetimbangan.
Contoh:
N2(g) + 3H2(g) « 2NH3(g)
Koefisien reaksi di kanan = 2
Koefisien reaksi di kiri = 4
-
Bila pada sistem kesetimbangan tekanan diperbesar (= volume diperkecil), maka kesetimbangan akan
bergeser ke kanan.
-
Bila pada sistem kesetimbangan tekanan diperkecil (= volume diperbesar), maka kesetimbangan akan
bergeser ke kiri.
C. PERUBAHAN SUHU
Menurut Van't Hoff:
-
Bila pada sistem kesetimbangan subu dinaikkan, maka kesetimbangan reaksi akan bergeser ke arah yang membutuhkan kalor (ke arah reaksi endoterm).
-
Bila pada sistem kesetimbangan suhu diturunkan, maka kesetimbangan reaksi akan bergeser ke arah yang membebaskan kalor (ke arah reaksi eksoterm).
Contoh:
2NO(g) + O2(g) « 2NO2(g) ; DH = -216 kJ
-
Jika suhu dinaikkan, maka kesetimbangan akan bergeser ke kiri.
-
Jika suhu diturunkan, maka kesetimbangan akan bergeser ke kanan.
PENGARUH KATALISATOR TERHADAP KESETIMBANGAN
Fungsi katalisator dalam reaksi kesetimbangan adalah mempercepat tercapainya kesetimbangan dan tidak merubah letak kesetimbangan (harga tetapan kesetimbangan Kc tetap), hal ini disebabkan katalisator mempercepat reaksi ke kanan dan ke kiri sama besar.
HUBUNGAN ANTARA HARGA Kc DENGAN Kp
Untuk reaksi umum:
a A(g) + b B(g) « c C(g) + d D(g)
Harga tetapan kesetimbangan:
Kc = [(C)c . (D)d] / [(A)a . (B)b]
Kp = (PCc x PDd) / (PAa x PBb)
dimana: PA, PB, PC dan PD merupakan tekanan parsial masing-masing gas A, B. C dan D.
Secara matematis, hubungan antara Kc dan Kp dapat diturunkan sebagai:
Kp = Kc (RT) Dn
dimana Dn adalah selisih (jumlah koefisien gas kanan) dan (jumlah koefisien gas kiri).
Contoh:
Jika diketahui reaksi kesetimbangan:
CO2(g) + C(s) « 2CO(g)
Pada suhu 300o C, harga Kp= 16. Hitunglah tekanan parsial CO2, jika tekanan total dalaun ruang 5 atm!
Jawab:
Misalkan tekanan parsial gas CO = x atm, maka tekanan parsial gas CO2 = (5 - x) atm.
Kp = (PCO)2 / PCO2 = x2 / (5 - x) = 16 ® x = 4
Jadi tekanan parsial gas CO2 = (5 - 4) = 1 atm
Disosiasi adalah penguraian suatu zat menjadi beberapa zat lain yang lebih sederhana.
Derajat disosiasi adalah perbandingan antara jumlah mol yang terurai dengan jumlah mol mula-mula.
Contoh:
2NH3(g) « N2(g) + 3H2(g)
besarnya nilai derajat disosiasi (a):
a = mol NH3 yang terurai / mol NH3 mula-mula
Harga derajat disosiasi terletak antara 0 dan 1, jika:
a = 0 berarti tidak terjadi penguraian
a = 1 berarti terjadi penguraian sempurna
0 < a < 1 berarti disosiasi pada reaksi setimbang (disosiasi sebagian).
Contoh:
Dalam reaksi disosiasi N2O4 berdasarkan persamaan
N2O4(g) « 2NO2(g)
banyaknya mol N2O4 dan NO2 pada keadaan setimbang adalah sama.
Pada keadaan ini berapakah harga derajat disosiasinya ?
Jawab:
Misalkan mol N2O4 mula-mula = a mol
mol N2O4 yang terurai = a a mol ® mol N2O4 sisa = a (1 - a) mol
mol NO2 yang terbentuk = 2 x mol N2O4 yang terurai = 2 a a mol
Pada keadaan setimbang:
mol N2O4 sisa = mol NO2 yang terbentuk
a(1 - a) = 2a a ® 1 - a = 2 a ® a = 1/3
Reaksi yang dapat berlangsung dalam dua arah disebut reaksi dapat balik. Apabila dalam suatu reaksi kimia, kecepatan reaksi ke kanan sama dengan kecepatan reaksi ke kiri maka, reaksi dikatakan dalam keadaan setimbang. Secara umum reaksi kesetimbangan dapat dinyatakan sebagai:
A + B ® C + D
ADA DUA MACAM SISTEM KESETIMBANGAN, YAITU :
1.
Kesetimbangan dalam sistem homogen
a.
Kesetimbangan dalam sistem gas-gas
Contoh: 2SO2(g) + O2(g) « 2SO3(g)
b.
Kesetimbangan dalam sistem larutan-larutan
Contoh: NH4OH(aq) « NH4+(aq) + OH- (aq)
2.
Kesetimbangan dalam sistem heterogen
a.
Kesetimbangan dalam sistem padat gas
Contoh: CaCO3(s) « CaO(s) + CO2(g)
b.
Kesetimbangan sistem padat larutan
Contoh: BaSO4(s) « Ba2+(aq) + SO42- (aq)
c.
Kesetimbangan dalam sistem larutan padat gas
Contoh: Ca(HCO3)2(aq) « CaCO3(s) + H2O(l) + CO2(g)
Hukum Guldberg dan Wange:
Dalam keadaan kesetimbangan pada suhu tetap, maka hasil kali konsentrasi zat-zat hasil reaksi dibagi dengan hasil kali konsentrasi pereaksi yang sisa dimana masing-masing konsentrasi itu dipangkatkan dengan koefisien reaksinya adalah tetap.
Pernyataan tersebut juga dikenal sebagai hukum kesetimbangan.
Untuk reaksi kesetimbangan: a A + b B « c C + d D maka:
Kc = (C)c x (D)d / (A)a x (B)b
Kc adalah konstanta kesetimbangan yang harganya tetap selama suhu tetap.
BEBERAPA HAL YANG HARUS DIPERHATIKAN
-
Jika zat-zat terdapat dalam kesetimbangan berbentuk padat dan gas yang dimasukkan dalam, persamaan kesetimbangan hanya zat-zat yang berbentuk gas saja sebab konsentrasi zat padat adalah tetap den nilainya telah terhitung dalam harga Kc itu.
Contoh: C(s) + CO2(g) « 2CO(g)
Kc = (CO)2 / (CO2)
-
Jika kesetimbangan antara zat padat dan larutan yang dimasukkan dalam perhitungan Kc hanya konsentrasi zat-zat yang larut saja.
Contoh: Zn(s) + Cu2+(aq) « Zn2+(aq) + Cu(s)
Kc = (Zn2+) / (CO2+)
-
Untuk kesetimbangan antara zat-zat dalam larutan jika pelarutnya tergolong salah satu reaktan atau hasil reaksinya maka konsentrasi dari pelarut itu tidak dimasukkan dalam perhitungan Kc.
Contoh: CH3COO-(aq) + H2O(l) « CH3COOH(aq) + OH-(aq)
Kc = (CH3COOH) x (OH-) / (CH3COO-)
Contoh soal:
1. Satu mol AB direaksikan dengan satu mol CD menurut persamaan reaksi:
AB(g) + CD(g) « AD(g) + BC(g)
Setelah kesetimbangan tercapai ternyata 3/4 mol senyawa CD berubah menjadi AD dan BC. Kalau volume ruangan 1 liter, tentukan tetapan kesetimbangan untuk reaksi ini !
Jawab:
Perhatikan reaksi kesetimbangan di atas jika ternyata CD berubah (bereaksi) sebanyak 3/4 mol maka AB yang bereaksi juga 3/4 mol (karena koefsiennya sama).
Dalam keadaan kesetimbangan:
(AD) = (BC) = 3/4 mol/l
(AB) sisa = (CD) sisa = 1 - 3/4 = 1/4 n mol/l
Kc = [(AD) x (BC)]/[(AB) x (CD)] = [(3/4) x (3/4)]/[(1/4) x (1/4)] = 9
2. Jika tetapan kesetimbangan untuk reaksi:
A(g) + 2B(g) « 4C(g)
sama dengan 0.25, maka berapakah besarnya tetapan kesetimbangan bagi reaksi:
2C(g) « 1/2A(g) + B(g)
Jawab:
- Untuk reaksi pertama: K1 = (C)4/[(A) x (B)2] = 0.25
- Untuk reaksi kedua : K2 = [(A)1/2 x (B)]/(C)2
- Hubungan antara K1 dan K2 dapat dinyatakan sebagai:
K1 = 1 / (K2)2 ® K2 = 2
Azas Le Chatelier menyatakan: Bila pada sistem kesetimbangan diadakan aksi, maka sistem akan mengadakan reaksi sedemikian rupa sehingga pengaruh aksi itu menjadi sekecil-kecilnya.
Perubahan dari keadaan kesetimbangan semula ke keadaan kesetimbangan yang baru akibat adanya aksi atau pengaruh dari luar itu dikenal dengan pergeseran kesetimbangan.
Bagi reaksi:
A + B « C + D
KEMUNGKINAN TERJADINYA PERGESERAN
1.
Dari kiri ke kanan, berarti A bereaksi dengan B memhentuk C dan D, sehingga jumlah mol A dan Bherkurang, sedangkan C dan D bertambah.
2.
Dari kanan ke kiri, berarti C dan D bereaksi membentuk A dan B. sehingga jumlah mol C dan Dherkurang, sedangkan A dan B bertambah.
FAKTOR-FAKTOR YANG DAPAT MENGGESER LETAK KESETIMBANGAN ADALAH :
a. Perubahan konsentrasi salah satu zat
b. Perubahan volume atau tekanan
c. Perubahan suhu
A. PERUBAHAN KONSENTRASI SALAH SATU ZAT
Apabila dalam sistem kesetimbangan homogen, konsentrasi salah satu zat diperbesar, maka kesetimbangan akan bergeser ke arah yang berlawanan dari zat tersebut. Sebaliknya, jika konsentrasi salah satu zat diperkecil, maka kesetimbangan akan bergeser ke pihak zat tersebut.
Contoh: 2SO2(g) + O2(g) « 2SO3(g)
- Bila pada sistem kesetimbangan ini ditambahkan gas SO2, maka kesetimbangan akan bergeser ke kanan.
- Bila pada sistem kesetimbangan ini dikurangi gas O2, maka kesetimbangan akan bergeser ke kiri.
B. PERUBAHAN VOLUME ATAU TEKANAN
Jika dalam suatu sistem kesetimbangan dilakukan aksi yang menyebabkan perubahan volume (bersamaan dengan perubahan tekanan), maka dalam sistem akan mengadakan berupa pergeseran kesetimbangan.
Jika tekanan diperbesar = volume diperkecil, kesetimbangan akan bergeser ke arah jumlah Koefisien Reaksi Kecil.
Jika tekanan diperkecil = volume diperbesar, kesetimbangan akan bergeser ke arah jumlah Koefisien reaksi besar.
Pada sistem kesetimbangan dimana jumlah koefisien reaksi sebelah kiri = jumlah koefisien sebelah kanan, maka perubahan tekanan/volume tidak menggeser letak kesetimbangan.
Contoh:
N2(g) + 3H2(g) « 2NH3(g)
Koefisien reaksi di kanan = 2
Koefisien reaksi di kiri = 4
-
Bila pada sistem kesetimbangan tekanan diperbesar (= volume diperkecil), maka kesetimbangan akan
bergeser ke kanan.
-
Bila pada sistem kesetimbangan tekanan diperkecil (= volume diperbesar), maka kesetimbangan akan
bergeser ke kiri.
C. PERUBAHAN SUHU
Menurut Van't Hoff:
-
Bila pada sistem kesetimbangan subu dinaikkan, maka kesetimbangan reaksi akan bergeser ke arah yang membutuhkan kalor (ke arah reaksi endoterm).
-
Bila pada sistem kesetimbangan suhu diturunkan, maka kesetimbangan reaksi akan bergeser ke arah yang membebaskan kalor (ke arah reaksi eksoterm).
Contoh:
2NO(g) + O2(g) « 2NO2(g) ; DH = -216 kJ
-
Jika suhu dinaikkan, maka kesetimbangan akan bergeser ke kiri.
-
Jika suhu diturunkan, maka kesetimbangan akan bergeser ke kanan.
PENGARUH KATALISATOR TERHADAP KESETIMBANGAN
Fungsi katalisator dalam reaksi kesetimbangan adalah mempercepat tercapainya kesetimbangan dan tidak merubah letak kesetimbangan (harga tetapan kesetimbangan Kc tetap), hal ini disebabkan katalisator mempercepat reaksi ke kanan dan ke kiri sama besar.
HUBUNGAN ANTARA HARGA Kc DENGAN Kp
Untuk reaksi umum:
a A(g) + b B(g) « c C(g) + d D(g)
Harga tetapan kesetimbangan:
Kc = [(C)c . (D)d] / [(A)a . (B)b]
Kp = (PCc x PDd) / (PAa x PBb)
dimana: PA, PB, PC dan PD merupakan tekanan parsial masing-masing gas A, B. C dan D.
Secara matematis, hubungan antara Kc dan Kp dapat diturunkan sebagai:
Kp = Kc (RT) Dn
dimana Dn adalah selisih (jumlah koefisien gas kanan) dan (jumlah koefisien gas kiri).
Contoh:
Jika diketahui reaksi kesetimbangan:
CO2(g) + C(s) « 2CO(g)
Pada suhu 300o C, harga Kp= 16. Hitunglah tekanan parsial CO2, jika tekanan total dalaun ruang 5 atm!
Jawab:
Misalkan tekanan parsial gas CO = x atm, maka tekanan parsial gas CO2 = (5 - x) atm.
Kp = (PCO)2 / PCO2 = x2 / (5 - x) = 16 ® x = 4
Jadi tekanan parsial gas CO2 = (5 - 4) = 1 atm
Disosiasi adalah penguraian suatu zat menjadi beberapa zat lain yang lebih sederhana.
Derajat disosiasi adalah perbandingan antara jumlah mol yang terurai dengan jumlah mol mula-mula.
Contoh:
2NH3(g) « N2(g) + 3H2(g)
besarnya nilai derajat disosiasi (a):
a = mol NH3 yang terurai / mol NH3 mula-mula
Harga derajat disosiasi terletak antara 0 dan 1, jika:
a = 0 berarti tidak terjadi penguraian
a = 1 berarti terjadi penguraian sempurna
0 < a < 1 berarti disosiasi pada reaksi setimbang (disosiasi sebagian).
Contoh:
Dalam reaksi disosiasi N2O4 berdasarkan persamaan
N2O4(g) « 2NO2(g)
banyaknya mol N2O4 dan NO2 pada keadaan setimbang adalah sama.
Pada keadaan ini berapakah harga derajat disosiasinya ?
Jawab:
Misalkan mol N2O4 mula-mula = a mol
mol N2O4 yang terurai = a a mol ® mol N2O4 sisa = a (1 - a) mol
mol NO2 yang terbentuk = 2 x mol N2O4 yang terurai = 2 a a mol
Pada keadaan setimbang:
mol N2O4 sisa = mol NO2 yang terbentuk
a(1 - a) = 2a a ® 1 - a = 2 a ® a = 1/3
Jumat, 11 Februari 2011
expressing certainty
Expressing certainty
YOUR QUESTIONS ANSWERED with FADZILAH AMIN
WHAT is the difference between the following two sentences:-
(i) I will throw a party.
(ii) I will be throwing a party.
2. I find the following passage not quite right, especially the part that is underlined. I am however unable to tell for sure what is wrong, if any. Please help.
“We can master a language if we are determined. Keen interest in a language is another factor that helps a language learner to master a language than those who do not have interest in mastering a language.”
— JT
Sentence (ii) which uses the future continuous tense, expresses more certainty than sentence (i) which uses the simple future tense. In fact, a time is usually mentioned in a sentence using the future continuous tense, e.g. “I will be throwing a party sometime next month.”
2. The word “than” in the second sentence indicates that a comparison is being made. But what is being compared is not stated. A few changes can be made to the second sentence to make it clear and logical. I have typed my suggestions for changes in bold and removed some words I consider unnecessary:
“We can master a language if we are determined. Having a keen interest in a language is another factor that helps some language learners master a language more quickly than those learners who are less interested in it.”
The main change I made is in indicating what is being compared, i.e. the time taken to master a language by keenly interested learners compared to the time taken by those who are not so interested.
Proper pronunication
Could you please define and show me how to pronounce these words:
Encore, enclave, entrée, en passant, entrepot, penchant
— Uncertain
Let me first tell you how I will indicate the British English pronunciations of the words, since some phonetic symbols cannot be printed here. These words are of French origin, but some of them have been somewhat anglicised in pronunciation.
I will indicate the “o” sound as in “got” with an “o”, and the vowel sound as in “rose” with an “oe”. An underlined “o” indicates a nasalised “o”, the way the second syllable of the Malay word “calon” would be pronounced in Kelantanese accent.
An “ei” indicates a vowel sound as in “lay”, while a bolded “e” indicates schwa, the sound in the first syllable of “ago”. An “ae” indicates the vowel sound as in “bat”.
I will also indicate a long vowel sound with a colon ( : ) after the vowel, and the stressed syllable in a word with a single quotation mark ( ‘ ) before it.
encore is pronounced /‘ong-ko:/
“Encore!” is what an audience calls out to a singer or musician in appreciation of his performance and as a request for him to sing another song or play another piece of music. If he obliges, the extra song or piece of music is also called an “encore”.
enclave is pronounced /‘en-kleiv/
An “enclave” is a part of the territory of one country surrounded by the territory of one or more other countries. Ceuta and Melilla which belong to Spain but are on African soil are examples of enclaves (see map). Below is some information from a BBC website about these enclaves:
“Ceuta and Melilla, fragments of Europe on north Africa’s Mediterranean coast, came under Spanish control around 500 years ago. Madrid says the urban enclaves are integral parts of Spain. They are surrounded by Morocco.... The enclaves are surrounded by fences, intended to deter illegal immigrants. But Ceuta and Melilla are nonetheless used by many Africans as stepping-stones to Iberia [Spain and Portugal]”
http://news.bbc.co.uk/2/hi/europe/country_profiles/4209538.stm
The word can also be used metaphorically to mean “a group of people who are culturally, intellectually or socially distinct from those surrounding them”(Concise Oxford Dictionary) Here is an example of its use:
“It is particularly troubling that American Indian reservations remain enclaves of the poor in one of the richest countries in the world.” (Scott Selk, South Dakota Business Review, June 1 2003)
http://www.allbusiness.com/north-america/united-states-south-dakota/602480-1.html
entrée is pronounced /‘on-trei/
An “entrée” can mean 1) the main dish in a Western restaurant or formal dinner, or 2) the right of admission (to a social group, for instance).
en passant is pronounced / o ‘paes-o /
“En passant” means “in passing”, i.e. mentioning something briefly while talking about something else. Here’s an example of its use in a sentence:
“While teaching us the life-cycle of a butterfly, our Biology teacher mentioned en passant that his wife had just had a baby, without saying whether it was a boy or a girl.”
entrepot is pronounced /‘on-tre-poe/
The most common meaning of “entrepot” is a commercial centre where goods are brought to be imported or exported. It could be a port or some other place used for this purpose. The word can also mean a duty-free port or a warehouse where goods in transit are temporarily stored.
penchant is pronounced /‘po-sho /
A penchant means an inclination towards something or a liking for something, e.g. “She has a penchant for Bollywood films” or “I have a penchant for Italian food”.
YOUR QUESTIONS ANSWERED with FADZILAH AMIN
WHAT is the difference between the following two sentences:-
(i) I will throw a party.
(ii) I will be throwing a party.
2. I find the following passage not quite right, especially the part that is underlined. I am however unable to tell for sure what is wrong, if any. Please help.
“We can master a language if we are determined. Keen interest in a language is another factor that helps a language learner to master a language than those who do not have interest in mastering a language.”
— JT
Sentence (ii) which uses the future continuous tense, expresses more certainty than sentence (i) which uses the simple future tense. In fact, a time is usually mentioned in a sentence using the future continuous tense, e.g. “I will be throwing a party sometime next month.”
2. The word “than” in the second sentence indicates that a comparison is being made. But what is being compared is not stated. A few changes can be made to the second sentence to make it clear and logical. I have typed my suggestions for changes in bold and removed some words I consider unnecessary:
“We can master a language if we are determined. Having a keen interest in a language is another factor that helps some language learners master a language more quickly than those learners who are less interested in it.”
The main change I made is in indicating what is being compared, i.e. the time taken to master a language by keenly interested learners compared to the time taken by those who are not so interested.
Proper pronunication
Could you please define and show me how to pronounce these words:
Encore, enclave, entrée, en passant, entrepot, penchant
— Uncertain
Let me first tell you how I will indicate the British English pronunciations of the words, since some phonetic symbols cannot be printed here. These words are of French origin, but some of them have been somewhat anglicised in pronunciation.
I will indicate the “o” sound as in “got” with an “o”, and the vowel sound as in “rose” with an “oe”. An underlined “o” indicates a nasalised “o”, the way the second syllable of the Malay word “calon” would be pronounced in Kelantanese accent.
An “ei” indicates a vowel sound as in “lay”, while a bolded “e” indicates schwa, the sound in the first syllable of “ago”. An “ae” indicates the vowel sound as in “bat”.
I will also indicate a long vowel sound with a colon ( : ) after the vowel, and the stressed syllable in a word with a single quotation mark ( ‘ ) before it.
encore is pronounced /‘ong-ko:/
“Encore!” is what an audience calls out to a singer or musician in appreciation of his performance and as a request for him to sing another song or play another piece of music. If he obliges, the extra song or piece of music is also called an “encore”.
enclave is pronounced /‘en-kleiv/
An “enclave” is a part of the territory of one country surrounded by the territory of one or more other countries. Ceuta and Melilla which belong to Spain but are on African soil are examples of enclaves (see map). Below is some information from a BBC website about these enclaves:
“Ceuta and Melilla, fragments of Europe on north Africa’s Mediterranean coast, came under Spanish control around 500 years ago. Madrid says the urban enclaves are integral parts of Spain. They are surrounded by Morocco.... The enclaves are surrounded by fences, intended to deter illegal immigrants. But Ceuta and Melilla are nonetheless used by many Africans as stepping-stones to Iberia [Spain and Portugal]”
http://news.bbc.co.uk/2/hi/europe/country_profiles/4209538.stm
The word can also be used metaphorically to mean “a group of people who are culturally, intellectually or socially distinct from those surrounding them”(Concise Oxford Dictionary) Here is an example of its use:
“It is particularly troubling that American Indian reservations remain enclaves of the poor in one of the richest countries in the world.” (Scott Selk, South Dakota Business Review, June 1 2003)
http://www.allbusiness.com/north-america/united-states-south-dakota/602480-1.html
entrée is pronounced /‘on-trei/
An “entrée” can mean 1) the main dish in a Western restaurant or formal dinner, or 2) the right of admission (to a social group, for instance).
en passant is pronounced / o ‘paes-o /
“En passant” means “in passing”, i.e. mentioning something briefly while talking about something else. Here’s an example of its use in a sentence:
“While teaching us the life-cycle of a butterfly, our Biology teacher mentioned en passant that his wife had just had a baby, without saying whether it was a boy or a girl.”
entrepot is pronounced /‘on-tre-poe/
The most common meaning of “entrepot” is a commercial centre where goods are brought to be imported or exported. It could be a port or some other place used for this purpose. The word can also mean a duty-free port or a warehouse where goods in transit are temporarily stored.
penchant is pronounced /‘po-sho /
A penchant means an inclination towards something or a liking for something, e.g. “She has a penchant for Bollywood films” or “I have a penchant for Italian food”.
Bargaining
Beijing Tips - Bargaining
Bargaining is the rule here in Beijing. At least, at the many markets and back-street clothes stalls. Bargaining is an art and if you are unfamiliar with it we'd like to offer you some advice. The tips here are Beijing specific but may help you at any place in the world where bargaining is practiced.
DO NOT say how much you want to pay for an item unless its near the end of the process. Always try and drop the seller's offering price as much as possible before opening your mouth with a price.
DO throw out really low prices like 10 RMB as long as you have a big smile.
DO keep smiling throughout. The seller is much more likely to continue bargaining with a happy smiling face. Getting angry rarely gets you the price you want.
BE AWARE the initial price offered by the seller is usually at least 40% over the general price acceptable. It can be up to 500% over.
DO have an idea of what the item is worth. You can ask Chinese friends, hotel staff, ex-pats or look at our rough guide below. This is very general and is based on a market like Xiu Shui. You may not be able to get the lowest prices stated at Xiu Shui, especially on a weekend when there are lots of tourists around.
Item (all fake brands) Price range (in RMB)
Pants/Trousers 50 - 120
Shirts/Tops 40 - 120
Jackets (non leather) 60 - 200
Shoes 30 - 150
Watches 30 - 300
DVD 6 - 20 (max)
VCD/CD 4 - 15 (max)
DO walk away once you've given them your final price, even before. If you get called back, you know you are close. If you do not get called back, go to a similar stall and try again with a slightly higher price.
The Process (illustrated)
The English being spoken by the seller will often consist of "cheaper", "how much you pay", "good quality", "no profit", "highest price". Numbers are tapped out on a giant calculator to avoid confusion.
Your best bet is to keep repeating the phrase "cheaper" to them as much as you can before revealing your price.
Decide on your price based on the chart above, how much you like it, and your perception of the quality of the item.
Once you've decided the price, you then tell them a figure about 40% of the price you're willing to pay, then go up in 5% increments until they give in.
A Successful Beijing Bargaining Example
You (looking at a nice pair of fake Calvin Klein pants)
How much ?
Seller 500
You (You look and decide the pants are worth about 100 to you)
Cheaper !
Seller How much you want to pay ?
(never answer this straight away, just look the pants over many times, ask why such a high price, remind them its a fake, find holes etc.)
You Cheaper !
Seller 300
You 40
Seller No. No ... these are real Calvin Klein pants, good quality .. 280
You 50
Seller 200
You (laughing)
60
Seller Ok, ok, last price, last price 160
You Ok, ok, last price 70
Seller These good pants must be at least 100
You 80
Seller No, no, sorry, no profit.
You Ok, sorry ... (start walking away)
Seller (calls you back, put items in bag)
Ok 90 !
You Ok 85 !!
Seller Ok sold... wow, you good negotiator.
You look at the above table and think, well, if things go this well I will have really gotten a deal. The fact is, if the seller still has a smile on his face, you haven't got the best deal possible. Our resident expert negotiator colleague will leave the seller with a look of real pain on his face. In the above example you could have got them for 50... but what the hell, you had fun and you got a great deal by western standards. Also, you'll be happy to know the seller and their family can eat a little better tonight.
Just a word on how NOT to Bargain. Here are some of the common mistake deals we've seen.
A Bad Beijing Bargaining Example 1
You (looking at a nice pair of fake Calvin Klein pants)
How much ?
Seller 500
You Ok. Great. Thanks.
As Homer Simpson would say ... "Doh !".
A Bad Beijing Bargaining Example 2
You (looking at a nice pair of fake Calvin Klein pants)
How much ?
Seller 500
You (Ha ! thinking you are going to show him !)
400
Seller 450
You 425
Seller Ok. Deal. You're killing me !
The way to avoid the situation in Example 2 is to have a much better idea of what the item is worth. Remember, once you state any price, the only place you can go from there is UP !
Bargaining is the rule here in Beijing. At least, at the many markets and back-street clothes stalls. Bargaining is an art and if you are unfamiliar with it we'd like to offer you some advice. The tips here are Beijing specific but may help you at any place in the world where bargaining is practiced.
DO NOT say how much you want to pay for an item unless its near the end of the process. Always try and drop the seller's offering price as much as possible before opening your mouth with a price.
DO throw out really low prices like 10 RMB as long as you have a big smile.
DO keep smiling throughout. The seller is much more likely to continue bargaining with a happy smiling face. Getting angry rarely gets you the price you want.
BE AWARE the initial price offered by the seller is usually at least 40% over the general price acceptable. It can be up to 500% over.
DO have an idea of what the item is worth. You can ask Chinese friends, hotel staff, ex-pats or look at our rough guide below. This is very general and is based on a market like Xiu Shui. You may not be able to get the lowest prices stated at Xiu Shui, especially on a weekend when there are lots of tourists around.
Item (all fake brands) Price range (in RMB)
Pants/Trousers 50 - 120
Shirts/Tops 40 - 120
Jackets (non leather) 60 - 200
Shoes 30 - 150
Watches 30 - 300
DVD 6 - 20 (max)
VCD/CD 4 - 15 (max)
DO walk away once you've given them your final price, even before. If you get called back, you know you are close. If you do not get called back, go to a similar stall and try again with a slightly higher price.
The Process (illustrated)
The English being spoken by the seller will often consist of "cheaper", "how much you pay", "good quality", "no profit", "highest price". Numbers are tapped out on a giant calculator to avoid confusion.
Your best bet is to keep repeating the phrase "cheaper" to them as much as you can before revealing your price.
Decide on your price based on the chart above, how much you like it, and your perception of the quality of the item.
Once you've decided the price, you then tell them a figure about 40% of the price you're willing to pay, then go up in 5% increments until they give in.
A Successful Beijing Bargaining Example
You (looking at a nice pair of fake Calvin Klein pants)
How much ?
Seller 500
You (You look and decide the pants are worth about 100 to you)
Cheaper !
Seller How much you want to pay ?
(never answer this straight away, just look the pants over many times, ask why such a high price, remind them its a fake, find holes etc.)
You Cheaper !
Seller 300
You 40
Seller No. No ... these are real Calvin Klein pants, good quality .. 280
You 50
Seller 200
You (laughing)
60
Seller Ok, ok, last price, last price 160
You Ok, ok, last price 70
Seller These good pants must be at least 100
You 80
Seller No, no, sorry, no profit.
You Ok, sorry ... (start walking away)
Seller (calls you back, put items in bag)
Ok 90 !
You Ok 85 !!
Seller Ok sold... wow, you good negotiator.
You look at the above table and think, well, if things go this well I will have really gotten a deal. The fact is, if the seller still has a smile on his face, you haven't got the best deal possible. Our resident expert negotiator colleague will leave the seller with a look of real pain on his face. In the above example you could have got them for 50... but what the hell, you had fun and you got a great deal by western standards. Also, you'll be happy to know the seller and their family can eat a little better tonight.
Just a word on how NOT to Bargain. Here are some of the common mistake deals we've seen.
A Bad Beijing Bargaining Example 1
You (looking at a nice pair of fake Calvin Klein pants)
How much ?
Seller 500
You Ok. Great. Thanks.
As Homer Simpson would say ... "Doh !".
A Bad Beijing Bargaining Example 2
You (looking at a nice pair of fake Calvin Klein pants)
How much ?
Seller 500
You (Ha ! thinking you are going to show him !)
400
Seller 450
You 425
Seller Ok. Deal. You're killing me !
The way to avoid the situation in Example 2 is to have a much better idea of what the item is worth. Remember, once you state any price, the only place you can go from there is UP !
invitation
Invitation Letters
How to write a warm and friendly invitation letter:
1.
The tone of an invitation should be always positive, in anticipation of a pleasurable occasion. Picture your guests smiling when they read your letter of invitation. Clever phrasing, poetry or a themed approach may be appropriate for an informal occasion, but you should express the details clearly.
2.
Extend the invitation, naming the event and including the date, time, and place. If the event has a special purpose, such as honoring someone or celebrating an anniversary, state this.
3.
Indicate if a gift is not expected if the event is a retirement, an anniversary, or a reception. If a gift is welcome, it is usually best to say nothing, except in the case of bridal or baby showers.
4.
Indicate the appropriate dress, if there is any reason for question.
5.
Express anticipation.
6.
Ask for a response by a specific date.
7.
Try to send your invitation letter two weeks or more in advance.
Be sure your invitation letter includes:
*
The name of the person sponsoring the event (who is the host/hostess?)
*
Exactly who is invited (can someone bring a guest, spouse, child?)
*
What type of social event is being held
*
The date, address, and time of the event
*
Directions or a simple map if the location may be difficult to find
*
What type of dress is appropriate or preferred
*
The phone number and deadline to reply; precede these facts with “RSVP” (French abbreviation for “please reply”).
If you must decline to accept an offer, invitation, or gift, you should:
*
Be gracious, whatever the reason is that you must decline.
*
Thank the person for the invitation, offer, gift, suggestion, etc.
*
State clearly that you are unable to accept.
*
Briefly state the reason that you are unable to accept, if desired.
*
In closing, restate your appreciation for the person’s consideration.
How to write a warm and friendly invitation letter:
1.
The tone of an invitation should be always positive, in anticipation of a pleasurable occasion. Picture your guests smiling when they read your letter of invitation. Clever phrasing, poetry or a themed approach may be appropriate for an informal occasion, but you should express the details clearly.
2.
Extend the invitation, naming the event and including the date, time, and place. If the event has a special purpose, such as honoring someone or celebrating an anniversary, state this.
3.
Indicate if a gift is not expected if the event is a retirement, an anniversary, or a reception. If a gift is welcome, it is usually best to say nothing, except in the case of bridal or baby showers.
4.
Indicate the appropriate dress, if there is any reason for question.
5.
Express anticipation.
6.
Ask for a response by a specific date.
7.
Try to send your invitation letter two weeks or more in advance.
Be sure your invitation letter includes:
*
The name of the person sponsoring the event (who is the host/hostess?)
*
Exactly who is invited (can someone bring a guest, spouse, child?)
*
What type of social event is being held
*
The date, address, and time of the event
*
Directions or a simple map if the location may be difficult to find
*
What type of dress is appropriate or preferred
*
The phone number and deadline to reply; precede these facts with “RSVP” (French abbreviation for “please reply”).
If you must decline to accept an offer, invitation, or gift, you should:
*
Be gracious, whatever the reason is that you must decline.
*
Thank the person for the invitation, offer, gift, suggestion, etc.
*
State clearly that you are unable to accept.
*
Briefly state the reason that you are unable to accept, if desired.
*
In closing, restate your appreciation for the person’s consideration.
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