Grade 12 Chemistry entrance exam 2009 – SMART ETHIO E-Learning

Welcome to your chemistry 2009

DIRECTIONS: Each of the following questions is followed by four possible alternatives.
You may refer to the information given below when you work on some of the questions.
PHYSICAL CONSTANTS:
Gas constant, R = 8.314J mol^-1 K^-1= 0.0821L - atm mol^-1
Avogadro's number = 6.023 x 10²³mol^-1
Plank's constant, h = 6.626 x 10^-34Js^-1
Energy, 1eV = 1.602 x 10⁸J
Speed of light, c= 2.9979 x 10^-18ms^-1
Faraday's constant(F) = 96500Cmol^-1e
Charge of 1 mole of electrons = 96500C = 1F
SI Units and Conversation Factors
1ton = 907.185 kg
1metic ton = 1000kg
1Å = 10^-10m
1L-atm = 101.3J
Coulombs = amperes x seconds
ATOMIC NUMBERS (Z) AND ATOMIC WEIGHTS (A)

Element	H	He	Li	B	C	N	O	F	Ne	Na	Mg	P	S	Cl	Ca	Cr	Mn	Fe
Z	1	2	3	5	6	7	8	9	10	11	12	15	16	17	20	24	25	26
A	1.0	4.1	6.9	10.8	12.0	14.0	16.0	19.0	20.2	22.98	24.31	30.97	32.1	35.5	40.1	52.0	54.9	55.9

Element	Co	Ni	Cu	Zn	Ag	Cd	Pt	Au	Hg
Z	27	28	29	30	47	48	78	79	80
A	58.9	58.7	63.5	65.4	107.9	112.4	195.08	197.0	200.6

1.

Which of the following covalent bonds is the most polar?

H - F

H - C

H - H

H - N

2.

The force that hold different atoms or ions together are called?

Electric forces

Physical bonds

Chemical bond

Atomic forces

3.

How many electrons are shared between two atoms in a double bond?

2

3

4

6

4.

Which of the following is the correct Lewis structure for oxygen atom?

Three lone- pairs of valence electrons

One lone- pair of valence electrons and one bonding site.

Two lone- pairs of valence electrons and one bonding site.

Two lone- pairs of valence electrons and two bonding sites.

5.

What is the chemical formula of the compound formed by aluminium (III) and sulphate ion, SO42- ?

AlSO4

Al2SO4

Al2(SO4

Al(SO4)3

6.

Which of the following is the most reasonable valence- bond structure of the nirocyl chloride (NOCl)?

7.

What is the ground state electronic configuration of Cu2+?

[Ar] 4st 3d8

[Ar] 4s2 3d7

[Ar] 4s1 3d10

[Ar] 3d9

8.

Which of the following is the correct order for electrons filling in orbitals?

3s, 3p, 4s, 3d

2p, 3s, 3p, 3d

3p, 4s, 3d, 5s

4s, 3d, 4p, 4d

9.

The normal human eye responds to visible light of wavelength ranging from about 390nm to 710nm. What is the frequency range of the human eye?

7.7 x 1014s-1 to 4.2 x 1014 s-1

4.2 x 1014s-1 to 7.7 x 1014 s-1

1.3 x 10-15s-1 to 2.4 x 10-15s-1

2.4 x 10-15s-1 to 1.3 x 10-15s-1

10.

How many different types of orbitals are there in the third energy level?

2

3

6

7

11.

The Heisenberg uncertainty principle states that

Two atoms of the same element must have the same number of protons.

No two electrons din the same atom can have the same set of four quantum numbers.

It is impossible to determine both position and momentum of an electron simultaneously.

Electrons of atoms in ground state enter energetically equivalent stet of orbitals singly before they pair any orbitals of the set.

12.

Which of the following transitions will have minimum wavelength?

n4 → n1

n2 → n1

n4 → n2

n3 → n1

13.

What is the energy associated with one photon of a microwave radiation having a frequency of 2.45 x 109s-1?

1.62 x 1024J

2.45 x 109J

2.45 x 10-9J

1.62 x 10-24J

14.

What is the frequency of a radiation (in Hz) from an atom if its wavelength is 1.0 x 10-9nm?

3.3 x 10-27

3.0 x 1017

3.0 x 108

3.0 x 1026

15.

Which of the following particle was discovered by the cathode rays experiment?

Electron

Neutron

Nucleus

Proton

16.

Which of the following is NOT a laboratory safety rule?

You should tie back loose hair.

You should never add acid to water.

Do not suck solution in the pipette by mouth.

When lighting a Bunsen Burner, you should light the match stick before turning on the gas.

17.

Which of the following are the correct steps of the Scientific Method?

Observation- Hypothesis- Experimentation- Formulation of Laws- Theories.

Observation- Formulation of Laws- Experimentation- Hypothesis- Theories

Observation- Experimentation- Hypothesis- Formulation of Laws- Theories

Observation- Experimentation- Formulation of Laws- Hypothesis- Theories

18.

Which of the following is the correct relationship between picometer (PM) and nanometer (nm)?

1Pm = 10nm

1pm = 100nm

1nm = 10pm

1nm = 1000pm

19.

How many significant figures has the sum of 2.453, 4.6 and 8.14?

2

3

4

5

20.

Which one of the following measurements has the greatest number of significant figures?

0.00046

0.0046

460

4.6 x 106

21.

Which of the following methods is used to convert oils into fats?

Esterification reaction using strong bases like NaOH or KOH

Saponification reaction using strong bases like NaOH or KOH

Hydrolysis reaction in the presence of water and a catalyst

Hydrogenation reaction at high temperature and in the presence of a catalyst

22.

The solubility of compounds containing the carboxylic acid group can be increased by reaction with

Sulphuric acid

Sodium hydroxide

Water

Benzoic acid

23.

What is the IUPAC name for the following molecule?

γ - amino - α - hydroxybutyric acid

4 - amino - 2 - hydroxybutanoic acid

1 - amino - 3 - hydroxybutanoic acid

α - amino - γ - hydroxybutyric acid

24.

What products will be formed when a carboxylic acid reacts with an alcohol?

Ketone and water

Amide and water

Acid chloride and water

Easter and water

25.

Consider the reaction

AB₃ (g) ⇌ A (g) + 3B (g)
What is the equilibrium constant expression if the initial concentration of AB₃, is 0.1M and the equilibrium concentration of A is expressed by x?
(Assume the initial concentrations of A and B are both zero.)

26.

Consider the following reaction at equilibrium.

2CO₂ (g) ⇌ 2CO (g) + O₂ (g) ∆H⁰ = -514KJ
What does Le Chatelier's principle predict when the temperature for the reaction is increased?

The value of the equilibrium constant will increase.

The value of the equilibrium constant will decrease.

The partial pressure of O2 (g) at equilibrium will increase.

The partial pressure of CO2 (g) at equilibrium will increase.

27.

For one component system, when would the degree of freedom becomes one?

When only one phase is present.

When two phases are present at equilibrium.

When three phases are present at equilibrium.

At all times.

Use the following equilibrium reaction for questions 29
2C (s) + O₂ (g) = 2CO (g) ∆H < 0

28.

For the reaction: 2C (s) + O2 (g) = 2CO (g) ∆H < 0 if the reaction is at equilibrium with excess C (s) remaining, what change will increase the quantity of CO (g) for the reaction at equilibrium?

1) Adding C (s)
2) Decreasing the temperature
3) Increasing the pressure

Only 1

Only 2

1 and 2

2 and 3

29.

Which one of the following is correct when a reaction reaches equilibrium?

The reaction rate for the forward direction is decreased to zero.

The rate of the forward and reverse reaction becomes equal.

The rate of the reverse reaction is reached a maximum.

The amounts of reactants and products becomes equal.

30.

A possible mechanism for the reaction, A + 2B → AB2 is

Step: A + B → AB Slow
Step: AB + B → AB2 Fast
Overall: A + 2B → AB₂
According to the mechanism, what will be the rate law?

Rate = K[A][B]

Rate = K[B]2

Rate = K[A][B]2

Rate = K[A]

31.

The initial rate of a reaction A + B → products was measured for several different starting concentrations of A and B, with the following results.

Exp	[A]	[B]	Initial rate of formation of C M/s
1	0.04	0.04	9.6 x 10^-6
2	0.08	0.04	1.92 x 10^-5
3	0.02	0.02	9.6 x 10^-6

What is the initial rate of reaction when [A]₀ = 0.12M and [B]₀ = 0.015M?

0.006Ms-1

0.006M-2s-1

1.08 x 10-5Ms-1

1.08 x 10-4Ms-1

32.

Given the following data for the reaction:

NH₄⁺(aq) + NO₂^-(aq) → N₂(g) + 2H₂O(l)

Experiment	[N₄⁺]	[N₂^-]	Rate
1	0.010M	0.020M	0.020M/s
2	0.015M	0.020M	0.03M/s
3	0.010M	0.010M	0.005M/s

What will be the rate law for the given reaction?

Rate = K[NH4+][NO2-]

Rate = K[NH4+]2[NO2]

Rate = K[NH4+]2[NO2-]2

Rate = K[NH4+][NO2-]2

33.

The rate of a reaction increases with increasing the concentration of reactant molecules, because

The average kinetic energy of the molecules increases.

The frequency of molecular collisions increase.

The order of the reaction increases

The activation energy increases.

34.

Consider the following reactions:

2N₂O₅(g) → 4NO₂(g) + O₂(g)
At a certain temperature, the rate of decomposition of N₂O₅(g) is 2.5 x 10⁶mol/s. What will be the rate of formation of NO₂?

1.0 x 10-5mol/s

2.5 x 10-6mol/s

1.3 x 10-6mol/s

5.0 x 10-6mol/s

35.

Which of the following refer to a reaction that is NOT dependent on the concentration of a reactant?

Second order reaction

First order reaction

Zero order reaction

Third order reaction

36.

What is (are) the F-S-F bond angle(s) in SF6?

109.50

1200

900 and 1200

900 and 1800

37.

What is the bond order of a superoxide anion, with the chemical formula O2-?

3

2.5

2

1.5

38.

What kind of hybrid orbitals are utilized by the carbon atom in CF4 molecules?

Sp

Sp2

Sp3

Sp3d

39.

Which of the following molecule is INCORRECTLY matched with the electronic geometry of the central atom?

CF4: tetrahedral

H2O: tetrahedral

CF4: Pyramidal

BeBr2: linear

40.

A 0.217g sample of HgO reacts with excess iodide ions according to the reaction:

HgO + 4I^- + H₂O → HgI₄^2- + 2OH^-
How many ml, of 0.1M HCl is required to reach equilibrium point during the titration of the solution?

1.0

10

20

50

41.

Which statement about indicators is always correct?

The mid-point of the PH rage of an indicator is 7.0

The PH rage is greater with higher PKa values.

The PKa values of the indicator is within its PH range.

42.

To a 50.0ml of a buffer solution that is 0.25M in HF and 0.10M in NaF, if 5.0ml of 0.050M NaOH is added, what is the final PH of this buffer solution? Given the pKaHF = 3.17

2.77

2.8

2.74

3.17

43.

The suppression of ionization of a weak acid or a weak base by adding one of its own ions is known as:

Buffer effect

Ionization effect

Common ion effect

Association effect

44.

Nitrous acid, HNO2 is 0.37% ionized in 3.0M solution. What is the Ka for this acid?

45.

Among the following acids, which has the lowest PKa value?

CH3CH2COOH

HCOOH

(CH3)2CHCOOH

CH3COOH

46.

Which one of the following is a Lewis acid?

NH3

CCl4

AlCl3

LiCl

47.

Which of the following is the conjugate acid of the HS-ion?

H2S-

S2-

S-

H2S

48.

What will be the ration of the boiling point elevation of a 0.1M solution of sucrose, sodium sulphate and potassium bromide?

1 : 3 : 1

1 : 1 : 2

1: 3 : 2

1 : 2 : 2

49.

When the molecular equation: CaCl2(aq) + Na2CO3(aq) → CaCO3(s) + 2NaCl(aq) Is written in terms of ionic equation, which one of the following pairs will be the spectator ions?

Na+ and Cl-

Ca2+ and Cl-

Na32- and Cl-

Ca2+ and CO32-

50.

If 0.454kg of nitroglycerin explodes according to the following reaction:

2C₃H₅ (NO₂)₃ → 6CO₂ + 3N₂ + 5H₂
What is the total volume of gases in dm³ produced at STP?

44.8

163

397.7

650

51.

How many grams of methanol would have to be added to water to prepare 150ml of solution which is 2.0M methanol?

2.4

9.6

9.6 x 103

4.3 x 102

52.

A certain 500g toothpaste sample has 0.2g of fluoride. What is the concentration of the fluoride in ppm?

200

250

400

1000

53.

What will be the normality of a 2.3M sulphuric acid solution?

0.23N

0.46N

2.3N

4.6N

54.

The solubility of NaCl in water at 200C is 36g in 100g of water. A solution that contains 18g of NaCl in 50g of water at 200C is

Saturated

Unsaturated

Supersaturated

Dilute

55.

Which of the following will increase the rate at which a solid dissolves in a liquid?

Supersaturating the solution

Grinding the solid into smaller pieces

Lowering the temperature of the solvent

Placing the solution in opaque container

56.

Which of the following pairs of substances are miscible?

Water and gasoline

Water and oxygen

Water and salt

Water and ethanol

57.

Which of the following types of solution are possible?

1. Solid dissolved in a liquid
2. Gas dissolved in a gas
3. Gas dissolved in a liquid
4. Solid dissolved in a solid

1 and 2

1, 2, 3 and 4

1, 2 and 4

1

58.

The chemical makeup of oil is esters of glycerol with three

Identical saturated fatty acids

Predominantly saturated fatty acids.

Predominantly unsaturated fatty acids.

Identical unsaturated fatty acids

59.

Which of the following general class of organic molecules do triglycerides belong to?

Ketones

Carboxylic acids

Esters

Ethers

60.

What type of polymerization occurs when amino acids react to form peptides and proteins?

Addition polymerization

Condensation polymerization

Substitution polymerization

Hydration polymerization

61.

Which of the following is the most abundant polysaccharide?

Amylose

Cellulose

Starch

Sucrose

62.

What is the other name for polymethyl methacrylate (PMMA)?

Perspex

Teflon

Bakelite

Nylon- 6

63.

What is the monomer of polyvinyl chloride (PVC)?

Cloroethane

Ethylene dichloride

Chloroform

Ethyl chloride

64.

The second step in the production of sulphuric acid is given by the reaction:

2SO₂(g) + O₂(g) ⇆ 2SO₃(g)
Which conditions would increase the yield of this reaction?

High temperature and low pressure

Low temperature and high pressure

High temperature and high pressure

Low temperature and low pressure

65.

Which of the following reactions is used in the production of industrially important chemical?

H2S2O7(l) + H2O(l) → 2H2SO4(aq)

3NO3(g) + H2O(l) → 2HNO3(aq) + NO2(g)

(NH4)2HPO4(s) + NH3(g) → NH4H2PO4(s)

2Cr(s) + Al2O3(s) → Cr2O3(s) + 2Al(s)

66.

Which one of the following metal is used for galvanization of iron sheets?

Nickel

Zinc

Chromium

Aluminium

67.

In what way is the phosphorous cycle differs from the carbon and nitrogen cycle?

Phosphorus is more abundant than carbon and nitrogen

Phosphorus is less important than carbon and nitrogen

Phosphorus, once used by an organism does not cycle back to the environment

The reservoirs for phosphorus exists in mineral form in rocks than in the atmosphere

68.

Which one of the following is needed for photosynthesis?

Carbon dioxide

Nitrogen

Oxygen

Phosphorus

69.

Consider the reaction:

Cu²⁺(aq) + Fe(s) ⇌ Cu(s) + Fe²⁺(aq), E0 = 0.78V
What is the value of E when [Cu²⁺] is equal to 0.040M and [Fe²⁺] is equal to 0.40M?

0.72V

0.75V

0.81V

0.84V

70.

For the electrochemical cell represented by:

Zn/ZnSO₄(aq) // CuSO₄(aq)/Cu(s)
The standard reduction potentials for Cu²⁺/Cu and Zn²⁺/Zn are +0.34 and -0.76V, respectively, what will be the cell reaction that occurs spontaneously and its cell voltage?

Cu + Zn2+ = Cu2+ + Zn E0(V) = 1.10

Zn + Cu2+ = Zn2+ + Cu E0(V) = 0.42

Cu2+ + Zn2+ = Zn + Cu E0(V) = 0.42

Cu2+ + Zn = Cu + Zn2+ E0(V) = 1.10

71.

What product(s) is /are formed during the electrolysis of a concentrated aqueous solution of sodium chloride?

Cl2(g)

Cl2(g) and H2(g)

NaOH(aq) and Cl2(g)

Cl2(g), H2(g) and NaOH(aq)

72.

In the reaction:

Pb+(s), PbO₂ + H₂SO₄(aq) → 2PbSO₄(s) + 2H₂O(l)
Which substance behaves as the oxidizing agent?

Pb

PbSO4

PbO2

H2SO4

73.

What mass of magnesium (Mg) is produced in the electrolysis of molten MgCl2, if a current of 7.50 x 102 A is passed through the molten salt for 1.00 hour?

3.4 x 102g

9.92 x 102g

1.7 x 102g

4.96 x 102g

74.

Devices in which oxidation- reduction reaction is induced by an electric current are called

Galvanic cells

Electrolytic cells

Voltaic cells

Electromotive cells

75.

In the following reaction:

3Cl^-(aq) + 4CrO₄^2-(aq) + 23H⁺(aq) → 3HClO₂(aq) + 4Cr³⁺(aq) + 10H₂O(l)
What is the behaviour Cl^- (aq)?

An acid

A base

An oxidizing agent

A reducing agent

76.

The KP for the reaction: 2SO3(g) ⇌ 2SO2(g) + O2(g) is 0.26 at 1,0000C and 40.8 at 1,3000C, which of the following combinations of ∆H and ∆S are most plausible for the reaction at these temperatures?

∆H ∆S

>0 <0

>0 >0

0

<0 <0

77.

Based on the following information

∆H⁰(KJ)
H₂(g) + 1/2O₂(g) → H₂O(l)                          -286
2Na(s) + 1/2O₂(g) → Na₂O(s)                      414
Na(s) +1/2O₂(g) + 1/2H₂(g) → NaOH(s)      -425
What will be the standard enthalpy changes for the reaction?
Na₂O(s) + H₂O(l) → 2NaOH(s)?

-978KJ

-722KJ

-150KJ

+275KJ

78.

At what condition(s) is the equation, ∆H = ∆U + P∆V, applicable?

For constant pressure and temperature processes

Only for constant pressure processes

Only for constant temperature processes

Only for constant volume processes

79.

What is a thermodynamic system that exchanges both energy and matter with the surroundings?

Adiabatic

Closed

Isolated

Open

Use the following equilibrium reaction for questions 81
2C (s) + O₂ (g) = 2CO (g) ∆H < 0

80.

What is the equilibrium expression? (M)

NATIONAL EDUCATIONAL ASSESMENT AND EXAMINATIONS AGENCY (NEAEA)ETHIOPIAN UNIVERSITY ENTRANCE EXAMINATION (EUEE)CHEMISTRY EXAMINTION 2009

NATIONAL EDUCATIONAL ASSESMENT AND EXAMINATIONS AGENCY (NEAEA)
ETHIOPIAN UNIVERSITY ENTRANCE EXAMINATION (EUEE)
CHEMISTRY EXAMINTION 2009