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Worksheets

OChem2

Total questions: 59

Worksheet time: 30mins

Name
Class
Date
1.

Which of the statements below accurately describe(s) alkanes

a)

They are least reactive class of organic compounds.

b)

All carbons in alkanes are ap' hybridized.

c)

Alkanes have no functional group.

d)

Alkanes contain only carbon-carbon single bonds

e)

All of the above

2.

A series of compounds, that differ only by the number of __________ groups is called a homologous series.

a)

-CH3

b)

-OH

c)

-NH2

d)

-CH2-

e)

>C=O

3.

Predict the molecular formula of a branched alkane that contains 55 carbon atoms

a)

C55 H110

b)

C55 H114

c)

C55 H112

d)

C55 H116

e)

C55 H115

4.

What is the correct IUPAC name for the following structure

a)

4-(2-bromo-1-methylethyl)-3-methylheptane

b)

3-(1-methylpropyl)-1-bromo-2-methylhexane

c)

1-bromo-2,4-dimethyl-3-propylhexane

d)

2,4-dimethyl-1-bromo-3-propylhexane

5.

How many secondary carbons are found in 5-ethyl-3,3,4-trimethylheptane

a)

2

b)

3

c)

5

d)

4

e)

1

6.

A branch alkane has _________ boiling point relative to the isomeric linear alkane Therefore there are ________ London force interactions in the branched alkane

a)

a higher, stronger

b)

a higher, weaker

c)

a lower, stronger

d)

a lower, weaker

e)

the same; similar

7.

What is the name of the compound below

a)

n-octane

b)

n-pentane

c)

n-propane

d)

n-hexane

e)

n-heptane

8.

Which of the statements below correctly describes the chair conformations of trans-1- ethyl-4-methylcyclohexane

a)

The higher energy chair conformation has both ethyl and methyl group in axial positions

b)

The higher energy chair conformation has both ethyl and methyl group in equatorial positions

c)

The lower energy chair conformation has the ethyl group in axial position and the methyl group in the equatorial position

d)

The lower energy chair conformation has the ethyl group in equatorial position and the methyl group in the axial position

e)

All of the above conformations have the same energy

9.

What is the relationship between the two structures below

a)

Constitutional isomers

b)

Conformational isomers

c)

Not isomers

d)

Degenerate isomers

e)

Cis-trans isomers

10.

Which of the following statements concerning the conformers of butane is true?

a)

The eclipsed and totally eclipsed conformation have the same amount of torsional strain.

b)

The lowest energy conformation of butane is the gauche conformation

c)

There is more torsional strain in the anti conformation than in the totally eclipsed conformation

d)

Butane spends most of the time in totally eclipsed conformation.

e)

The gauche and anti conformations differ primarily in the amount of torsional strain present

11.

Which of the following is true about the twist bond confirmation of cyclohexane

a)

Higher angle strain in the twist boat

b)

Lower angle strain in the twist boat

c)

Lower torsional strain in the twist boat

d)

Higher torsional strain in the twist boat

e)

None of the above is true

12.

____ is the study of energy chnages that accompany chemical and physical transformation

a)

Kinetics

b)

Entropy

c)

Mechanism

d)

Thermodynamics

e)

Enthalpy

13.

Which of the following occurs in the first propagation step of the free radical chlorination of methane?

a)

A Cl₂ molecule splits into two chlorine free radicals.

b)

A chlorine free radical abstracts a hydrogen atom from methane.

c)

A methyl radical reacts with a Cl₂ molecule.

d)

A methyl radical reacts with a chlorine free radical.

e)

Two chlorine free radicals combine to form a Cl₂ molecule

14.

Which of the following statements regarding cyclobutane is correct?

a)

The lowest energy conformation is one in which the bond angles are

slightly less than 90° even though this increases angle strain

b)

The lowest energy conformation of cyclobutane is a planar one in which all of the bond angles is 90°.

c)

The lowest energy conformation is one in which the bond angles are greater than 90° so that angle strain is significantly reduced

d)

The lowest energy conformation of cyclobutane is known as the chair conformation

e)

None of the above statements is correct

15.

Which of the following is true for the initiation step of a free radical chlorination reaction?

a)

∆H°> 0 and ∆S° <0

b)

∆H°> 0 and ∆S° >0

c)

∆H°< 0 and ∆S° >0

d)

∆H°< 0 and ∆S° <0

e)

∆H°= 0 and ∆S° =0

16.

How many monochlorinated products are possible in the free radical chlorination of propane?

a)

one

b)

two

c)

three

d)

four

e)

five

17.

Which of the following happens in exothermic reaction

a)

Stronger bonds are broken and weaker bonds are formed and energy is consumed.

b)

Weaker bonds are broken and stronger bonds are formed and energy is released

c)

Stronger bonds are broken and weaker bonds are formed and energy is released.

d)

Weaker bonds are broken and stronger bonds are formed and energy is consumed

e)

Bonds broken and bonds formed are of equal strength.

18.

Why does the rate of a reaction increase as the temperature is increased

a)

Because the molecules make more collisions with the wall of the reaction vessel

b)

Because the frequency factor (4) increases

c)

Because the activation energy decreases

d)

Because the fraction of molecules with kinetic energy greater than Ea increases

e)

Because the activation energy increases

19.

What is the heat of reaction (∆H°) for the following free-radical bromination?

Bond Dissociation Enthalpy:
CH3-H= +435
Ch3-Br= +293
Br-Br= +192
H-Br= +368

a)

-25 kJ/mol

b)

+34 kJ/mol

c)

+57 kJ/mol

d)

-34 kJ/mol

e)

-43 kJ/mol

20.

If ∆G° for a given reaction at 25° C is less than zero, which of the following correctly describes this reaction at this temperature

a)

The reaction must be exothermic

b)

The reaction must be endothermic

c)

Keq is greater than zero

d)

There is no change in temperature

e)

None of the above.

21.

The following is an example of an sn1 reaction. doubling the concentration of tert-butyl bromide [(CH3)C-Br] Causes the rate two double. doubling the concentration of hydroxide ion [-OH] has no effect on the rate of the reaction. what is the overall order of this reaction?

a)

First Order

b)

Second Order

c)

Third Order

d)

Fourth Order

e)

Fifth Order

22.

The following is an energy diagram for a two-step reaction. Which of following statements is not true regarding this diagram?

a)

First step is endothermic

b)

Second step is exothermic

c)

The reverse reaction is endothermic

d)

The reaction has an intermediate

e)

The reaction is endothermic overall

23.

What is the hybridization state of the carbon atom in the methyl free radical

a)

sp3

b)

sp1

c)

sp4

d)

sp2

e)

sp6

24.

Which of the following statements is true regarding the ring strain of cycloalkanes per CH2 groups:

a)

Cyclpentane has less ring strain per CH2 group than any other cycloalkane.

b)

Cyclobutane has more ring strain per CH2 group than any other cycloalkane

c)

Cyclopropane has more ring strain per CH2 group than any other cycloalkane

d)

Cyclohexane has less ring strain per CH2 group than any other eyeloalkane

e)

More than one of the above

25.

The graph below shows the relative torsional energies of the butane conformations Name the conformations that belong to the locations I, II, III, and IV respectively

a)

anti, eclipsed, gauche, totally eclisped

b)

totally eclipsed, anti, eclipsed, gauche

c)

gauche, totally eclipsed, anti, eclipsed

d)

eclipsed, gauche, totally eclipsed, anti

e)

totally eclipsed, gauche, eclipsed, anti

26.

A series of compounds, which differ only by the number of-CH2- groups, is called a(n) _____ series.

a)

alkane

b)

hydrocarbon

c)

saturated

d)

homologous

e)

alkene

27.

Triacontane is an unbranched alkane that contains 30 carbon atoms in each molecule. How many hydrogen atoms are present in each molecule of triacontane?

a)

30

b)

32

c)

58

d)

60

e)

62

28.

A linear alkane has ____ boiling point relative to the isomeric branched alkane. There are ____ London dispersion force interactions in the branched alkanes

a)

a higher, stronger

b)

a higher, weaker

c)

a lower, stronger

d)

a lower; weaker

e)

the same; similar

29.

What is the correct IUPAC name for the following structure

a)

4-(2-chloro-1-methylethyl)-3-methylhexane

b)

3-sec-butyl-1-chloro-2-methylhexane

c)

1-chloro-2,4-dimethyl-3-propylhexane

d)

2,4-dimethyl-1-chloro-3-propylhexane

e)

4-(2-chloro-1-methylethyl)-3-methylheptane

30.

Which of the statements below correctly describes the chair conformations of cis-1,4- dimethylcyclohexane?

a)

The higher energy chair conformation contains two axial methyl groups

b)

The higher energy chair conformation contains one axial methyl group and one equatorial methyl group

c)

The lower energy chair conformation contains one axial methyl group and one equatorial methyl group

d)

The two chair conformations are of equal energy

e)

The lower energy chair conformation contains two axial methyl groups

31.

Which of the following best describes the molecules of a sample of ethane gas at room temperature

a)

Almost all of the molecules are frozen or locked in the eclipsed conformation

b)

Almost all of the molecules are frozen or locked in the staggered conformation

c)

The molecules are rapidly interconverting between the eclipsed and staggered conformations, but at any one time slightly more of them are present in the eclipsed conformation

d)

The molecules are rapidly interconverting between the eclipsed and staggered conformations, but at any one time slightly more of them are present in the staggered conformation

e)

There will be a 50:50 mixture of eclipsed and staggered conformations.

32.

Which of the following correctly lists the conformations of cyclohexane in order of increasing energy?

a)

chair< boats< twist< half-chair

b)

half-chair<boat<twist<chair

c)

chair<twist<half-chair<boat

d)

chair<twist<boat<half-chair

e)

half-chair<twist<boat<chair

33.

Which of the following happens in endothermic reactions

a)

Stronger bonds are broken and weaker bonds are formed and energy is consumed

b)

Weaker bonds are broken and stronger bonds are formed and energy is released

c)

Stronger bonds are broken and weaker bonds are formed and energy is released

d)

Weaker bonds are broken and stronger bonds are formed and energy is consumed

e)

Bonds broken and bonds formed are of equal strength

34.

If the concentration of (CH3) 3 CBr is tripled, the rate of the reaction triples. If the concentration of CH3CH2OH is doubled, the rate of the reaction is unchanged. Which of the following correctly describes the kinetics of this reaction

a)

The reaction is third order in (CH3) 3 CBr

b)

The reaction is first order in CH3CH2OH

c)

The reaction is second order overall

d)

The reaction is first order overall

e)

None of the above

35.

How many monochlorinated products are possible in the chlorination of cyclopentane

a)

one

b)

two

c)

three

d)

four

e)

five

36.

Given the chlorination of acetone shown below, choose the correct rate equation

a)

rate k [CH3COCH3]

b)

rate k [Cl2]

c)

rate k [CH3COCH3] [Cl2]

d)

rate k [CH3COCH3] [Cl2]^1/2

e)

none of the above

37.

The following reaction has a value of ∆G°=-2.1kj/mol What is the K eq value at room temperature (25 °C) for this reaction? (R = 8.314J / K * mol)

CH3Br + HS -> CH3SH + HBr

a)

2.3

b)

5.6

c)

1.9

d)

3.2

e)

7.5

38.

Shown below is the bromination of cyclohexene. When the concentration of cyclohexene is doubled, the reaction rate doubles. When the concentration of bromine is doubled, the reaction rate quadruples (increases fourfold). What is the overall rate of the reaction?

a)

1st Order

b)

2nd Order

c)

3rd Order

d)

4th Order

e)

0th Order

39.

Which of the statements below is not true regarding alkanes

a)

They are least reactive class of organic compounds.

b)

They are called unsaturated hydrocarbons

c)

Alkanes have no functional group.

d)

They contain only hydrogen and sp2 hybridized carbon

e)

More than one of the above

40.

How many tertiary carbons are there in 3-ethyl-2,4,5-trimethylheptane

a)

2

b)

3

c)

5

d)

4

e)

1

41.

answer to the best of your abilities

a)

A

b)

B

c)

C

d)

D

e)

E

42.

answer

a)

A

b)

B

c)

C

d)

D

e)

E

43.

answer

a)

A

b)

B

c)

C

d)

D

e)

E

44.

Which of the following occurs in the secondary propagation step of the free radical chlorination of methane?

a)

A Cl₂ molecule splits into two chlorine free radicals.

b)

A chlorine free radical abstracts a hydrogen atom from methane.

c)

A methyl radical reacts with a Cl₂ molecule.

d)

A methyl radical reacts with a chlorine free radical.

e)

Two chlorine free radicals combine to form a Cl₂ molecule

45.

?

a)

A

b)

B

c)

C

d)

D

e)

E

46.

Which of the following happens in endothermic reaction

a)

Stronger bonds are broken and weaker bonds are formed and energy is consumed.

b)

Weaker bonds are broken and stronger bonds are formed and energy is released

c)

Stronger bonds are broken and weaker bonds are formed and energy is released.

d)

Weaker bonds are broken and stronger bonds are formed and energy is consumed

e)

Bonds broken and bonds formed are of equal strength.

47.

?

a)

A

b)

B

c)

C

d)

D

e)

E

48.

?

a)

A

b)

B

c)

C

d)

D

e)

E

49.

The graph below shows the relative torsional energies of the butane conformations Name the conformations that belong to the locations I, II, III, and IV respectively

a)

anti, eclipsed, gauche, totally eclisped

b)

totally eclipsed, anti, eclipsed, gauche

c)

gauche, totally eclipsed, anti, eclipsed

d)

eclipsed, gauche, totally eclipsed, anti

e)

totally eclipsed, gauche, eclipsed, anti

50.

?

a)

A

b)

B

c)

C

d)

D

e)

E

51.

?

a)

A

b)

B

c)

C

d)

D

e)

E

52.

?

a)

A

b)

B

c)

C

d)

D

e)

E

53.

?

a)

A

b)

B

c)

C

d)

D

e)

E

54.

?

a)

A

b)

B

c)

C

d)

D

e)

E

55.

?

a)

A

b)

B

c)

C

d)

D

e)

E

56.

?

a)

A

b)

B

c)

C

d)

D

e)

E

57.

?

a)

A

b)

B

c)

C

d)

D

e)

E

58.

answer to the best of your abilities

a)

A

b)

B

c)

C

d)

D

e)

E

59.

?

a)

A

b)

B

c)

C

d)

D

e)

E