AS LEVEL Organic Chemistry Questions: by Nerissa Puntawe

2015-03-04 08:47:22 UTC

An organic compound J reacts with sodium to produce an organic ion with a charge of –3. J reacts with NaOH(aq) to produce an organic ion with a charge of –1. What could be the structural formula of J? A HO2CCH(OH)CH2CO2H B HO2CCH(OH)CH2CHO C HOCH2CH(OH)CH2CO2H D HOCH2COCH2CHO

Ans-

Ron

2015-03-04 08:47:26 UTC

Ans- C

2015-03-04 08:47:31 UTC

Aiman

2015-03-04 08:48:44 UTC

C 4

Hege

2015-03-04 08:49:34 UTC

Aluminium chloride catalyses certain reactions by forming carbocations with chloroalkanes as
shown.
RCl + AlCl3 → R+ + AlCl4–
Which property makes this reaction possible?
A AlCl3 exists as the dimer Al2Cl6 in the vapour.
B AlCl3 is a covalent molecule.
C The aluminium atom in AlCl3 has an incomplete octet of electrons.
D The chlorine atom in RCl has a vacant p orbital.

a

2015-03-04 08:50:54 UTC

Brigitta

2015-03-04 08:50:54 UTC

Which reactions can be used to make an alcohol in the laboratory? 1 hydrolysis of a bromoalkane with NaOH(aq) 2 reduction of a ketone with NaBH4 3 reduction of an aldehyde with NaBH4

Answer D

Audi

2015-03-04 08:51:02 UTC

22 Bromine reacts with ethene to form 1,2-dibromoethane. What is the correct description

of the organic intermediate in this reaction?

A It has a negative charge.

B It is a free radical.

C It is a nucleophile.

D It is an electrophile.

Answer - D ( this is due to the bromine being an aceeptor of the electron )

Ron

2015-03-04 08:51:05 UTC

Ans- D

Alyca

2015-03-04 08:52:35 UTC

Ans - B

Steven

2015-03-04 08:52:48 UTC

Answer - D

Aiman

2015-03-04 08:53:18 UTC

Hegel

2015-03-04 08:55:21 UTC

An alkene has the formula CH3CH=CRCH2CH3 and does not possess cis-trans isomers.
What is R?
A H B Cl C CH3 D C2H5

Aiman

2015-03-04 08:55:37 UTC

Vincent

2015-03-04 11:01:32 UTC

Vincent

2015-03-04 11:06:08 UTC

Vincent

2015-03-04 11:13:51 UTC

Vincent

2015-03-04 11:13:52 UTC

Vincent

2015-03-04 11:23:24 UTC

Vincent

2015-03-04 11:35:07 UTC

Answer for number 4 (a) :

i. C2H5OH → C2H4 + H2O ii. Elimination Reaction

iii. Phosporic Acid

Vincent

2015-03-04 11:39:19 UTC

Answer for Number 4 (c):

i. C6H10

ii. (at the following picture)

iii. Addition

Vincent

2015-03-04 11:42:46 UTC

Answer for Number 4 (c) (ii) :

Brigitta

2015-03-04 11:45:51 UTC

5 The molecular formula C4H9OH represents four different alcohols, W, X, Y and Z. W X Y Z CH3CH2CH2CH2OH CH3CH2CH(OH)CH3 (CH3)2CHCH2OH, (CH3)3COH (a) Draw the skeletal formula of Z.
answer +O-H

Vincent

2015-03-04 11:47:56 UTC

Answer for Number 4 (a) : The double bond can break if the temperature is increases and at the same time, the pressure is also increases. both of these factors will cause the double bond will break and make the 2-butene into poly(butene)

Brigitta

2015-03-04 11:51:52 UTC

2.30 g of ethanol were mixed with an excess of aqueous acidified potassium dichromate(VI). The reaction mixture was then boiled under reflux for one hour. The desired organic product was then collected by distillation. The yield of product was 60.0 %. What mass of product was collected? A 1.32 g B 1.38 g C 1.80 g D 3.20 g

Answer C

Brigitta

2015-03-04 12:10:59 UTC

nucleophilic (1) substitution (1) NH3 (1)
free radical (1) substitution (1) Br2 or Br2 in an organic solvent

Brigitta

2015-03-04 12:16:57 UTC

How many isomeric esters have the molecular formula C4H8O2? A 2 B 3 C 4 D 5

Answer C

Brigitta

2015-03-04 12:18:21 UTC

colourless purple or pink
colourless colourless or decolourised
CH3CH2Br HOCH2CH2OH

Brigitta

2015-03-04 12:23:03 UTC

For Examiner’s Use (c) The operating conditions for this reaction are as follows. pressure 200 atmospheres (2 × 107 Pa) temperature 600 K catalyst oxides of Cr, Cu, and Zn In the spaces below, explain how each of these conditions affects the rate of formation of methanol. pressure ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... temperature ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... catalyst ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... [6]
pressure increases rate (1) by increasing frequency of collisions or by increasing concentration of reactants (1) temperature increases rate (1) because more molecules have energy >Ea (1) catalyst increases rate (1) by providing an alternative route of lower Ea (1) [6]

Brigitta

2015-03-04 12:29:37 UTC

The depletion of the ozone layer in the upper atmosphere reduces the Earth’s natural protection from harmful ultraviolet radiation. Which compound would cause the most depletion of the ozone layer? A CCl 3F B CF4 C CHCl F2 D CH2F2

Answer A

Brigitta

2015-03-04 12:38:17 UTC

Propan1ol

Brigitta

2015-03-04 12:41:09 UTC

When organic refuse decomposes in water carboxylic acids are formed. The water becomes acidic and aquatic life is destroyed. Which additives are suitable to remove this acid pollution? 1 calcium carbonate 2 calcium hydroxide 3 potassium nitrate

Answer B

Brigitta

2015-03-04 12:44:32 UTC

In a car engine, non-metallic element X forms a pollutant oxide Y. Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation, 1 mol of Y reacts with ½ mol of gaseous oxygen. What can X be? 1 carbon 2 nitrogen 3 sulfur

Answer

Alyca

2015-03-04 13:20:37 UTC

Complete combustion of compound X gives carbon dioxide and water only. A sample of X is mixed with aqueous potassium(V) dichromate and boiled under reflux for one hour. The mixture is then distilled and the only organic substance present is collected. The organic substance collected reacts with sodium to give hydrogen, but does not react with 2,4-dinitrophenylhydrazine reagent and does not react with ethanol in the presence of concentrated sulfuric acid to give an ester. What can be deduced from this information? A. X is a carboxylic acid. B . X is a ketone. C. X is an alcohol. D. X is an alkane.

Ans - C

Alyca

2015-03-04 13:24:25 UTC

A compound Y has the following properties. • It is a liquid at room temperature and atmospheric pressure. • It does not mix completely with water. • It does not give steamy fumes with PCl5. What could Y be? A ethane B ethanoic acid C ethanol D ethyl ethanoate

Alyca

2015-03-04 13:35:15 UTC

Pentane, C5H12, is reacted with chlorine in the presence of ultraviolet light. A compound R is found in the products. R has molecular formula C5H10Cl 2. Each molecule of R contains one chiral carbon atom. Which two atoms of the pentane chain could be bonded to chlorine atoms in this isomer? A 1 and 3

B 1 and 5

C 2 and 3

D 2 and 4

Ans - A

Alyca

2015-03-04 13:55:33 UTC

Ans - A

Steven

2015-03-04 14:59:11 UTC

Answer - C

Steven

2015-03-04 14:59:40 UTC

Answer - D

Steven

2015-03-04 15:00:36 UTC

Answer - C

Steven

2015-03-04 15:02:12 UTC

4. a) Reaction 1 =

Reagent: NaOH/KOH

Solvent: H2O

Reaction 2 =

Regent: NH3 (Ammonia)

Solvent: C2H5OH (Ethanol)

Reaction 3 =

Reagent: NaOH/KOH

Solvent: C2H5OH (Ethanol)

Steven

2015-03-04 15:04:28 UTC

4. b) With CH3CH2CH2CH2I rate would be faster

C - I bond is weaker than C - Br bond

C - I bond energy is 240 kJ mol-1

C- Br bond energy is 280 kJ mol -1

2015-03-04 16:38:11 UTC

Aiman

2015-03-04 16:38:42 UTC

ai) Alkanes

aii) C9H20 + 14O2 -> 9CO2 + 10H20

Aiman

2015-03-04 16:50:57 UTC

ai) Structural Isomer

aii) R = Primary Alcohol and Carboxylic Acid

S = Primary Alcohol and Ester

T = Primary Alcohol and Ester

aiii) carboxylic acid

aiv) alcohol and carboxylic acid

Aiman

2015-03-04 16:57:03 UTC

a) 117˚ to 120˚

b) i) Electrophilic addition

b ii (Aiman)

2015-03-04 16:59:14 UTC

Aiman

2015-03-04 17:15:34 UTC

ai) Alkanes

aii) 2C4H10 + 1302 -> 8C02 + 10H20

Aiman

2015-03-04 17:20:26 UTC

ai) H = CH2=CHCH2CH2OH, CH3CH=CHCH2OH, CH2=CHCH(OH)CH3

J = CH3CH2COCH3

K = CH3CH2CH2CHO

continue

2015-03-04 17:21:13 UTC

aii (Aiman)

2015-03-04 17:26:45 UTC

aii (Aiman)

2015-03-04 17:26:45 UTC

Vincent

2015-03-05 00:47:39 UTC

Answer for Number 2 (a):

i. cracking is the process of breaking the large hydrocarbons into smaller hydrocarbons. this process carried out because the smaller cabohydrons is more useful than the large one.

ii. cracking process is carried out by using high temperatures

iii. C14H30 → C7H16 + C7H14

Audi

2015-03-05 00:56:38 UTC

Answers:

a i). A = No reaction

B = CH3CH2CO2H

C = HCO2Na

D = CH2 = CHCH2OH

E= No reaction

F = No reaction

Vincent

2015-03-05 00:57:39 UTC

Answer for Number 2 (d):

i. enchanced greenhouse effect is when a gas trap some of the reflected light from the sun in the lower atmosphere and making the earth's temperature rises.

ii. CO

Audi

2015-03-05 04:12:53 UTC

a i). Carboxylic Acid

ii). Carboxylic Acid not present

iii). Alkene present

Steven

2015-03-05 04:21:10 UTC

W = CH3CH2CH2CH2OH

X = CH3CH2CH=CH2

Y = CH3CH2CH2CO2H

Z = CH3CH2CO2H

Steven

2015-03-05 04:22:35 UTC

Steven

2015-03-05 04:23:29 UTC

b) (i) X

(ii)

C2H5 H C2H5 H

| | | |

- C - C - C - C -

| | | |

H H H H

Steven

2015-03-05 04:28:34 UTC

4. B

Steven

2015-03-05 04:28:35 UTC

Answer - B

Steven

2015-03-05 04:28:36 UTC

4. B

Steven

2015-03-05 04:29:36 UTC

Answer - A

Adit

kresnodityo_j — 2015-03-05 04:40:12 UTC

5 Compounds containing the allyl group, CH2=CHCH2–, have pungent smells and are found in onions and garlic.

Allyl alcohol, CH2=CHCH2OH, is a colourless liquid which is soluble in water.

(a) Allyl alcohol behaves as a primary alcohol and as an alkene.

Give the structural formula of the organic compound formed when allyl alcohol is reacted separately with each of the following reagents.

(ii) bromine in an inert organic solvent

1 - bromopropane

(iii) cold, dilute, acidified potassium manganate(VII)

propa - 1,3 - diol

(iv) hot, concentrated, acidified potassium manganate(VII)

carbon dioxide

(b) Allyl alcohol undergoes the following reactions.

(i) When reacted with concentrated HCl at

100 °C, CH2=CHCH2Cl is formed.

State as fully as you can what type of reaction this is.

Substitution

(ii) When reacted with MnO2 at room temperature, CH2=CHCHO is formed.What type of reaction is this?

Oxidation

nerissa_p — 2015-03-05 04:47:01 UTC

nerissa_p — 2015-03-05 04:47:12 UTC

Audi

2015-03-05 04:49:32 UTC

Alyca

2015-03-05 04:53:54 UTC

Mr of S = 116 Mr of T = 134 Mr of U = 150

(ii) S

Audi

2015-03-05 04:54:14 UTC

answer for b(i.

Hegel

2015-03-05 04:56:00 UTC

Alyca

2015-03-05 04:59:26 UTC

S into T : H2SO4 and H2O

S into U : KMnO4

T into S : P4O10 and heat

Steven

2015-03-05 05:01:31 UTC

a) (i) C2H

Steven

2015-03-05 05:02:48 UTC

Steven

2015-03-05 05:02:48 UTC

b) (i) Functional group

(ii) Compound P = Cis-trans

Compound T = Optical (mirror)

Audi

2015-03-05 05:04:19 UTC

Ron

2015-03-05 05:04:40 UTC

Polymerisation of chloroethene gives PVC. How does the carbon-carbon bond in PVC compare with that in chloroethene? A longer and stronger B longer and weaker C shorter and stronger D shorter and weaker

Ans- B

Ron

2015-03-05 05:05:15 UTC

Trichloroethanoic acid, CCl3CO2H, is used in cosmetic surgery to perform a ‘chemical peel’ to remove dead skin. Trichloroethanoic acid can be made by reacting chlorine with ethanoic acid. What is the mechanism of this reaction? A electrophilic addition B electrophilic substitution C free radical addition D free radical substitution

Ans- D

Audi

2015-03-05 05:05:36 UTC

b i). answer

Ron

2015-03-05 05:07:11 UTC

0.200 mol of a hydrocarbon undergo complete combustion to give 35.2 g of carbon dioxide and 14.4 g of water as the only products. What is the molecular formula of the hydrocarbon? A C2H4 B C2H6 C C4H4 D C4H8

Ans- D

Alyca

2015-03-05 05:09:11 UTC

T = CH3CH2CH2CH2OH U = CH3CH2CO2H V = CH3CH2CH(OH)CH2OH W = CH3CH2COCO2H

Ron

2015-03-05 05:11:43 UTC

What always applies to a nucleophile? A It attacks a double bond. B It has a lone pair of electrons. C It is a single atom. D It is negatively charged.

Ans- B

Audi

2015-03-05 05:12:11 UTC

Ron

2015-03-05 05:12:14 UTC

Bromine reacts with ethene to form 1,2-dibromoethane. What is the correct description of the organic intermediate in this reaction? A It has a negative charge. B It is a free radical. C It is a nucleophile. D It is an electrophile.

Ans- D

Audi

2015-03-05 05:23:20 UTC

Audi

2015-03-05 05:30:39 UTC

i. Manufacture of ammonia through the Haber process

Audi

2015-03-05 05:45:09 UTC

3 Crude oil is a naturally occurring flammable liquid which consists of a complex mixture of hydrocarbons. In order to separate the hydrocarbons the crude oil is subjected to fractional distillation.

Explain what is meant by the following terms.

(i) hydrocarbon

(ii) fractional distillation

Answers:

3 (i) a compound which contains only carbon and hydrogen

(ii) separation of compounds by their boiling points

Audi

2015-03-05 05:49:14 UTC

Audi

2015-03-05 05:50:42 UTC

Audi

2015-03-05 05:52:25 UTC

Audi

2015-03-05 05:53:30 UTC

2015-03-05 06:10:10 UTC

Brigitta

2015-05-22 05:38:01 UTC

Brigitta

2015-05-22 05:38:43 UTC

Brigitta

2015-05-22 05:38:56 UTC

Brigitta

2015-05-22 05:39:11 UTC

Brigitta

2015-05-22 05:39:26 UTC

Brigitta

2015-05-22 05:39:39 UTC

Brigitta

2015-05-22 05:40:07 UTC

Brigitta

2015-05-22 05:40:43 UTC

Brigitta

2015-05-22 05:40:57 UTC

Brigitta

2015-05-22 05:41:18 UTC

2018-04-15 07:35:55 UTC

Lactic acid 2-hydroxipropanoic acid, CH3CH(OH)CO2H, is found in sour milk

rayajani17 — 2021-04-14 13:15:41 UTC

Ans-