Section I 1) Two elements X (Atomic mass 16) and Y (Atomic mass 14) combine to form compounds A, B

and C. the ratio of different masses of Y which combines with a fixed mass of X in A, B and C

is 1:3:5. If 32 parts by mass of X combines with 84 parts by mass of Y in B, then in C, 16 parts

by mass of X will combine with ………… parts by mass of Y.

a) 14

b) 42

c) 70

d) 84

2) Law of definite proportion does not apply to nitrogen oxide because

a) Atomic weight of nitrogen is not constant

b) Molecular weight of nitrogen is variable

c) Equivalent weight of nitrogen is variable

d) Atomic weight of oxygen is variable

3) In textile mill, a double effect evaporator system concentrates weak liquor containing 4% (by

weight) caustic soda to produce a lye containing 25% solids (by weight). Calculate the weight of

the water evaporate per 100 kg feed in the evaporator.

a) 125.0 g

b) 50.0 kg

c) 84.0 kg

d) 16.0 kg

4) Zinc ore (zinc sulphate) is treated with sulphuric acid, leaving a solution with some undissolved

bits of material and releasing hydrogen sulphide gas. If 10.8 g of zinc ore is treated with 50.0 mL

of sulphuric acid (density 1.153 g/mL), 65.1 g of solution and undissolved material remains. In

addition, hydrogen sulphide (density 1.393 g/L) is evolved. What is the volume (in litres) of this

gas?

a) 4.3

b) 3.35

c) 4.67

d) 2.40

5) A sample of an ethanol-water solution has a volume of 54.2 cm3 and a mass of 49.6 g. what is

the percentage of ethanol (by mass) in the solution? (Assume that there is no change in change in

volume when the pure compounds are mixed.) The density of ethanol is 0.80 g/cm3 and that of

water is 1.00 g/cm3.

a) 18.4%

b) 37.1%

c) 33.95%

d) 31.2%

6) Zinc metal reacts with yellow crystals of sulphur in a fiery reaction to produce a white powder of

zinc sulphide. A chemist determines that 65.4 of zinc reacts with 32.1 g of sulphur. How many

grams of zinc sulphide could be produced from 20.0 g of zinc metal?

a) 29.8 g

b) 9.8 g

c) 97.5 g

d) 31.8 g

7) A student gently drops an object weighting 15.8 g into an open vessel that is full of ethanol, so

that a volume of ethanol spills out equal to the volume of the object. The experimenter now finds

that the vessel and its contents weigh 10.5 g more than the vessel full of ethanol only. The

density of ethanol is 0.789 g/cm3. What is the density of the object?

a) 6.717 g/cm3

b) 4.182 g/cm3

c) 1.563 g/cm3

d) 2.352 g/cm3

8) A person needs 2.0 mg of riboflavin (Vitamin B2) per day on an average. How many gram of

butter should be taken by the person per day if it is the only source of riboflavin? Butter contains

5.5 microgram riboflavin per gram.

a) 363.6 g

b) 2.75 mg

c) 11 g

d) 19.8 g

9) A sample of clay contains 40% silica and 15% water. The sample is partially dried by which it

loses 5 g water. If the percentage of water in the partially dried clay is 8, calculate the percentage

of silica in the partially dried clay.

a) 21.33%

b) 43.29%

c) 75%

d) 50%

10) The density of quartz mineral was determined by adding a weighed piece to a graduated cylinder

containing 51.2 mL water. After the quartz was submersed, the water level was 65.7 mL. the

quartz piece weighed 38.4 g. what was the density of quartz?

a) 1.71 g/mL

b) 1.33 g/mL

c) 2.65 g/mL

d) 1.65 g/mL

11) Some bottles of colourless liquids were being labeled when the technicians accidently mixed

them up and lost track of their contents. A 15.0 mL sample withdrawn from one bottle weighed

22.3 g. The technicians knew that the liquid was either acetone, benzene, chloroform or carbon

tetrachloride (Which have densities of 0.792 g/cm3, 0.899 g/cm

3, 1.489 g/cm

3 and 1.595 g/cm

3,

respectively). What was the identity of the liquid?

a) Carbon tetrachloride

b) Acetone

c) Chloroform

d) Benzene

12) An ammonium sulphate solution of concentration 0.05 kilo mol reacts with calcium hydroxide.

How many litres of a solution (specific gravity 0.92) containing 20.5% by weight of ammonia

can be prepared using this reaction?

a) 12.0 L

b) 9.0 L

c) 18.0 L

d) 4.5 L

13) Atomic mass of an element is

a) The actual mass of the one atom of the element

b) The relative mass of an atom of the element

c) The average relative mass of different atoms of the element

d) Much different from the mass number of the element

14) The use of C12

scale has superseded the older scaled of atomic mass based on O18

isotope, one

important advantage of the former being

a) the atomic masses on C12

scale became whole numbers

b) C12

is more abundant in the earth’s crust than O16

c) The different between physical and chemical atomic masses got narrowed down significantly

d) C12

is situated midway between metals and non-metals in the periodic table

15) One atomic mass unit in kilogram is

a) 1/NA

b) 12/NA

c) 1/1000 NA

d) 1000/NA

16) An element, X, have three isotopes X20

, X21

and X22

. The percentage abundance of X20

is 90%

and its average atomic mass of the element is 20.18. The percentage abundance of X21

should be

a) 2%

b) 8%

c) 10%

d) 0%

17) The number of atoms present in 0.5 g atoms of nitrogen is same as the atoms in

a) 12 g of C

b) 32 g of S

c) 8 g of oxygen

d) 24 g of Mg

18) A graph is plotted for an element, by putting its weight on X-axis and the corresponding number

of number of atoms on Y-axis. Determine the atomic weight of the element for which the graph

is plotted.

a) Infinite

b) 40

c) 0.025

d) 20

19) The O18

/O16

ratio in some meteorites is greater than that used to calculate the average atomic

mass of oxygen on earth. The average mass of an atom of oxygen in these meteorites is

………… that of a terrestrial oxygen atom?

a) Equal to

b) Greater than

c) Less than

d) None of these

20) If isotopic distribution of C12

and C14

is 98.0% and 2.0% respectively, then the number of C14

atoms in 12 g of carbon is

a) 1.032 × 1022

b) 1.20 × 1022

c) 5.88 × 1023

d) 6.02 × 1023

21) At one time there was a chemical atomic weight scale based on the assignment of the value

16.0000 to naturally occurring oxygen. What would have been the atomic weight, on such a

table, of silver, if current information had been available? The atomic weights of oxygen and

silver on the present table are 15.9994 and 107.868.

a) 107.908

b) 107.864

c) 107.868

d) 107.872

22) In what atomic ratio O16

and O17

atoms should be taken in a sample such that average atomic

mass becomes 16.72?

a) 7:18

b) 18:7

c) 19:8

d) 8:19

23) Two isotopes of an element Q are Q97

(23.4% abundance) and Q94

(76.6% abundance). Q97

is

8.082 times heavier than C12

and Q94

is 7.833 times heavier than C12

. What is the average atomic

weight of the element Q?

a) 94.702

b) 78.913

c) 96.298

d) 94.695

24) The element silicon makes up 25.7% of the earth’s crust by weight, and is the second most

abundant element, with oxygen being the first. Three isotopes of silicon occur in nature; Si28

(92.21%), which has an atomic mass of 27.97693 u; Si29

(4.70%), with an atomic mass of

28.97649 u: and Si30

(3.09%), with an atomic mass of 29.97379 u. what is the atomic weight of

silicon?

a) 28.0856

b) 28.1088

c) 28.8342

d) 29.0012

25) The oxide of a metal contains 30% oxygen by weight. If the atomic ratio of metal and oxygen is

2:3, determine the atomic weight of metal.

a) 12

b) 56

c) 27

d) 52

26) The mercury content of a stream was believed to be above the minimum considered safe limit (1

part per billion by weight). An analysis indicated that the concentration was 1.68 parts per

billion. How many Hg atoms was present in 15 L of the water, the density of which is 0.998

g/mL? (Hg = 200)

a) 7.57 × 1013

b) 7.57 × 1019

c) 7.57 × 1016

d) 5.37 × 1016

27) There are 2.619 × 1022

atoms in 1.0 g of sodium. Assume that sodium atoms are spheres of

radius 0.186 nm and that they are lined up side by side. How many miles, its length, is the line of

sodium atoms?

a) 0.74 × 1012

b) 1.56 × 1010

c) 1.44 × 109

d) 6.089 × 109

28) Ammonia is a gas with a characteristic pungent odour. It is sold as a water solution by one in

household cleaning. The gas is a compound of nitrogen and hydrogen in the atomic ratio 1:3. A

sample of ammonia contains 7.933 g N and 1.712 g H. what is the atomic mass of N relative to

H?

a) 14

b) 27.80

c) 14.90

d) 14.10

29) The waste of nuclear power plant contains C12

and C14

in the ratio of 4:1 by moles. What is the

molecular weight of CH4 gas produced from this disposed waster? Given abundance of C12

and

C14

are 98% and 2% respectively.

a) 15.998

b) 16.0053

c) 16

d) 16.4

30) Pheromones are a special type of compound secreted by the females of many insect species to

attract the males for mating. One pheromone has the molecular formula C19H38O. Normally, the

amount of this pheromone secreted by a female insect is about 1 × 10–12

g. How many molecules

are in this quantity?

a) 1 × 1012

b) 3.55 × 1015

c) 2.135 × 109

d) 6.023 × 1023

31) Molecular weight of dry air is

a) Less than moist air

b) Greater than moist air

c) Equal to moist air

d) May be greater or less than moist air

32) At room temperature, the molar volume of hydrogen fluoride gas has a mass of about 50 g. The

formula weight of hydrogen fluoride is 20. Gaseous hydrogen fluoride at room temperature is

therefore, probably a mixture of

a) H2 and F2

b) HF and H2F2

c) HF and H2.5F2.5

d) H2F2 and H3F3

33) The density of a DNA sample is 1.1 g/mL and its molar mass determined by cryoscopic method

was found to be 6 × 108 g/mol. What is the volume occupied by one DNA molecule?

a) 5.45 × 108 mL

b) 1.83 × 10-9

mL

c) 9.06 × 10-16

mL

d) 1.09 × 10-13

mL

34) The density of a plant virus is 1.66 g/cm3. If each virus particles are spheres of diameter 6A , the

molecular weight of virus should be

a) 36π

b) 72π

c) 5.976 × 10-23

π

d) 18π

35) Total number of valence electrons present in 6.4 g peroxides ion (2

2O ) is

a) 0.2 NA

b) 3.2 NA

c) 3.6 NA

d) 2.8 NA

36) A gaseous mixture contains 70% N2 and 30% unknown gas, by volume. If the average

molecular weight of gaseous mixture is 37.60, the molecular weight of unknown gas is

a) 42.2

b) 60

c) 40

d) 50

37) A gaseous mixture contains CO2 and SO3. The average molecular weight of the mixture may be

a) 40

b) 80

c) 70

d) 90

38) The number of F– ions in 4.2 g AlF3 is

a) 0.05

b) 9.03 × 1022

c) 3.01 × 1022

d) 0.15

39) If the atomic mass were given by as 1

6th part and molecular mass as

1

12th part by mass of one

atom of C12

isotope, what would be the molecular mass of water? Atomic masses of hydrogen

and oxygen on new scale are, 1 and 16 respectively.

a) 18

b) 9

c) 36

d) unpredictable

40) Each molecule of a tear gas, lewisite contains 2 hydrogen atoms, 1.78 × 10–22

g chlorine, 2

carbon atoms and 1.25 × 10–22

g of an unknown metal. Its molecular weight will be

a) 195

b) 208.5

c) 280

d) 188.3

41) 20 molecules of SO3 will weigh as much as …………molecules of oxygen.

a) 100

b) 50

c) 15

d) 8

42) If the mass of neutron is doubled and that of proton is halved, the molecular weight of H2O

containing H1 and O

16 atoms only, will

a) Increase by about 25%

b) Decrease by about 25%

c) Increase by about 17%

d) Increase by about 14%

43) Which of the following contains largest number of oxygen atoms?

a) 2 g atomic oxygen

b) 2 g oxygen molecules

c) 2 g ozone molecules

d) All have same number

44) The number of hydrogen atoms in 0.9 g glucose, C6H12O6, is same as

a) 0.048 g hydrazine, N2H4

b) 0.17 g ammonia , NH3

c) 0.30 g ethane, C2H6

d) 0.03 g hydrogen, H2

45) Volume occupied by 6 g of a mixture of nitrogen and oxygen is 4.48 L at 1 atm and 0o

C. the

percentage by mass of nitrogen in the mixture is

a) 50%

b) 46.67%

c) 53.33%

d) 28%

46) The average density of the universe as a whole is estimated as 3 × 10–29

g per mL. If we assume

that the entire mass is only H atoms, what is the average volume of space that contains one H

atom?

a) 110 L

b) 9 × 10-6

L

c) 55 L

d) 220 L

47) The number of molecules present in 1 mL of an ideal gas at 273 K and 1 atm is called ------- and

its value is ………….

a) Avogrado’s number, 6.023 × 1023

b) Loschmidt number, 2.7 × 1019

c) Ryberg number, 1.09 × 107

d) Universal gas constant, 0.082 unit

48) Mass of one proton is 1.675 × 10–24

g. How many moles of proton are present in its 1 kg?

a) 4110

1.675 6.023

b) 10

1.675 6.023

c) 24110

6.75

d) 27110

1.675

49) Assuming that 1, 3, 5-hexatriene has only pure double bonds and pure single bonds, how many

grams of it contain one mole of double bonds?

a) 13.3 g

b) 26.7 g

c) 40 g

d) 80 g

50) 2 moles of H atoms at 1 atm and 0o C occupies a volume of

a) 11.2 L

b) 44.8 L

c) 2 L

d) 22.4 L

51) Which of the following will occupy greater volume under the similar conditions of pressure and

temperature?

a) 6 g oxygen

b) 0.98 g hydrogen

c) 5.25 g oxygen

d) 1.32 g helium

52) The degree of dissociation, α, (dt is the theoretical density of original compound and d0 is the

observed density of the sample of compound) be calculated by using the formula α = t 0

0

d -d

(n-1)d.

This formula is applicable at

a) Constant volume and constant temperature

b) Constant volume and variable temperature

c) Constant pressure and constant temperature

d) All of the above condition

53) 112.0 mL of NO2 at 1 atm and 0o C was liquefied, the density of the liquid being 1.15 g.mL

-1.

Calculate the volume and the number of molecules in the liquid NO2.

a) 0.10 mL and 3.01 × 1022

b) 0.20 mL and 3.01 × 1021

c) 0.20 mL and 6.02 × 1023

d) 0.40 mL and 6.02 × 1021

54) In an experiment, it is found that 2.0769 g of pure X produces 3.6769 g of pure X2O5. The

number of moles of X is

a) 0.04

b) 0.06

c) 0.40

d) 0.02

55) The volume occupied by 20 g water at 1.2 atm and 4o C is about

a) 20 mL

b) 20 0.082 227

L18 1.2

c) 20 0.082 4

L18 1.2

d) 20 L

56) If common-salt (molecular weight = 58.5) costs Rs. 7.00 per kg and sugar (molecular weight =

342) costs Rs. 14.00 per kg, what would be the cost of 1 mole of salt and sugar?

a) Both will have the same cost

b) The cost of sugar will be half the cost of salt

c) The cost of sugar will be more than that of salt

d) The cost of sugar will be twice the cost of salt

57) Number of g-atoms of oxygen present in 0.8 mole of tartaric acid C4H6O6 would be

a) 3.6

b) 1.8

c) 2.4

d) 4.8

58) Equal masses of oxygen, hydrogen and methane are taken in identical conditions. What is the

ratio of the volumes of the gases under identical conditions?

a) 16 : 1 : 8

b) 1: 16 : 2

c) 1 : 16 : 8

d) 2: 16 : 1

59) While resting, the average 70 kg human male consumes 14 L of oxygen per hour at 25oC and

100 kPa. How many moles of oxygen are consumed by the 70 kg man while resting for 1 hour?

a) 0.57

b) 57292.5

c) 0.58

d) 58037.32

60) 3.0 g of a solid compound produced 672 mL of a gas at STP (1 atm and 0oC), on strong heating.

After the reaction the weight of the solid residue was 1.68 g. what is the molecular weight of the

gas obtained?

a) 19.84

b) 25.25

c) 44

d) 39.6

61) When a sample of hydrogen fluoride is cooled to 303 K, most of the molecules undergo

dimerisation. If the vapour density of such a sample is 19, what percent of hydrogen fluoride

molecules are in dimer form? (F = 19)

a) 94.7

b) 89.9

c) 97.3

d) 5.3

62) 2.3 g of a mixture of NO2 and N2O4 has a pressure of 0.82 atm, at temperature T K in a container

of volume V litres such that the ratio, T:V is 300:1 in magnitude. What is the degree of

dissociation of N2O4?

a) 0.17

b) 0.33

c) 0.67

d) 0.70

63) 1 kg of each substance is taken. Which of them will have largest mass of nitrogen?

a) KNO3

b) NH3NO3

c) (NH4)3HPO4

d) HNO3

64) A 10 g sample of ore containing 2.8 g of HgS. What is the percentage of mercury in the ore? (Hg

= 200, S = 32)

a) 24.1

b) 29.01

c) 2-------

d) 39

65) The mineral haematite is Fe2O3. Haematite ore contains unwanted material called gangue in

addition of Fe2O3. If 5 kg of ore contains 2.78 kg of Fe, what percentage of ore is gangue? (Fe =

56)

a) 55.6%

b) 44.4%

c) 20.6%

d) 79.4%

66) The hydrated salt Na2SO4.nH2O undergoes 55.9% loss in weight on heating and becomes

anhydrous. The value of n will be

a) 5

b) 3

c) 7

d) 10

67) The commonly used pain reliever, aspirin, has the molecular formula C9H8O4. If a sample of

aspirin contains 0.968 g of carbon, what is the mass of hydrogen in the sample?

a) 0.717 g

b) 0.0717 g

c) 8.000 g

d) 0.645 g

68) For CuSO4.5H2O which is the correct mole relationship?

a) 9 × mole of Cu = mole of O

b) 5 × mole of Cu = mole of O

c) 9 × mole of Cu = mole of O2

d) mole of Cu = 5 × mole of O

69) Nitrogen (N), phosphorus (P) and potassium (K) are the main nutrients in plant fertilizers.

According to an industry convention, the number on the label refer to the mass percent of N,

P2O5 and K2O, in that order. What is N : P : K ratio of a 30 : 10 : 10 fertilizer in terms of moles

of atoms of each element, expressed as x : y : 1.0? (N = 14, P = 31, K = 39)

a) 10 : 0.66 : 1.0

b) 20 : 0.66 : 1.0

c) 8.4 : 1.3 : 1.0

d) 16.8 : 1.3 : 1.0

70) Chloroflurocarbons such as CCl3F (M = 137.5) and CCl2F2 (M = 121) have been linked to ozone

depletion in Antartica. As of 2004, these gases were found in 275 and 605 parts per trillion

(1012

), by volume. What are the concentrations of these gases under conditions typical of

Antartic stratosphere (200 K and 0.05 atm)?

a) [CCl3F] = 8.38 × 10–13

mol L–1

, [CCl3F] = 1.84 × 10–12

mol L–1

b) [CCl3F] = 2.00 × 10–12

mol L–1

, [CCl3F] = 5.00 × 10–12

mol L–1

c) [CCl3F] = 2.00 × 10–9

mol L–1

, [CCl3F] = 5.00 × 10–9

mol L–1

d) [CCl3F] = 6.56 × 10–7

mol L–1

, [CCl3F] = 1.64 × 10–8

mol L–1

71) Caffeine has a molecular mass of 194. If it contains 28.9% by mass of nitrogen, number of

atoms of nitrogen in one molecule of caffeine is

a) 4

b) 6

c) 2

d) 3

72) A certain mixture of MnO and MnO2 contains 66.67 mol % of MnO. What is the approximate

weight percent of Mn in it? (Mn = 55)

a) 66.67

b) 33.33

c) 72

d) 28

73) A compound contains 36% carbon by weight. If each molecule contains two carbon atoms, the

number of moles of compound in its 10 g is

a) 66.67

b) 0.15

c) 0.30

d) 0.60

74) What will be percentage concentration of a solution that is obtained by mixing 300 g of 25%

solution of NaCl with 150 g of 40% solution of NaCl? All percentage are mass percentages.

a) 25%

b) 30%

c) 35%

d) 40%

75) In the Dumas method, 0.2 g of an organic nitrogenous compound gave 27 mL of N2 (volume

reduced to 1 atm and 0oC). what is the percentage of nitrogen by weight in the compound?

a) 16.9

b) 19.6

c) 33.1

d) 13.3

76) 0.2 of an organic compound containing, C, H and O, on combustion yielded 0.147 g CO2 and

0.12 g water. The percentage of oxygen in it is

a) 73.29%

b) 78.45%

c) 83.23%

d) 89.50%

77) Haemoglobin of a blood corpuscle contains 0.33% iron. The molecular weight of haemoglobin

was found to be 67000 g. What is the number of iron atoms present in each molecule of

haemoglobin? (Atomic weight of Iron = 56)

a) 2

b) 3

c) 4

d) 5

78) The empirical formula of an organic compound containing carbon and hydrogen is CH2. The

mass of the one litre of this organic gas is exactly equal to that of one litre of nitrogen, under

identical conditions. Therefore, the molecular formula of the organic gas is

a) C2H4

b) C3H6

c) C6H12

d) C4H8

79) 60 g of an organic compound has 24 g carbon and rest hydrogen and oxygen. The empirical

formula of the compound is

a) C2H8O2

b) C2H4O

c) CH4O

d) CH2O

80) A hydride of silicon prepared by the reaction of Mg2Si with acid exerted a pressure of 306 torr of

299 K, in a bulb of capacity 57 mL. If the mass of the hydride was --------- g, what is its

molecular formula? (Si = 28)

a) SiH4

b) Si2H6

c) Si3H8

d) Si3H6

81) A compound have carbon, hydrogen and oxygen in 3 : 3 : 1 atomic ratio. If the number of moles

in 1 g of compound is 6.06 × 10–3

, the molecular formula of the compound will be

a) C3H3O

b) C6H6O2

c) C9H9O3

d) C12H12O4

82) On analysis, a certain compound was found to contain iodine and oxygen in the ratio of 254 g of

iodine and 80 g of oxygen. The atomic mass of iodine is 127 and that of oxygen is 16. Which of

the following is the formula of compound?

a) IO

b) I2O

c) I3O4

d) I2O5

83) Iron forms two oxides. For the same amount of iron, amount of oxygen combined in the first

oxide is two-third of the amount of oxygen combined in the second oxide, the ratio of valencies

of iron in first and second oxide is

a) 1 : 1

b) 2 : 3

c) 3 : 2

d) 2 : 5

84) A compound contains equal masses of the elements A, B and C. If the atomic weights of A, B

and C are 20, 40 and 60 respectively, the empirical formula of compound is

a) A3B2C

b) AB2C3

c) ABC

d) A6B3C2

85) A compound contains elements X and Y in 1 : 4 mass ratio. If the atomic masses of X and Y are

in 1 : 2 ratio, the empirical formula of compound should be

a) XY6

b) X2Y

c) XY4

d) X4Y

86) A semiconductor, YBa2Cu3O7, is prepared by a reduction involving Y2O3, BaO2 and Cu2O. The

mole ratio in which these compound should combine, is

a) 1 : 2 : 4

b) 1 : 2 : 3

c) 1 : 4 : 6

d) 1 : 3 : 4

87) Assume that the atomic weight of oxygen is 7. A sample of 11 g of an oxide of uranium contains

10 g of uranium. Which of the following formula for the oxide is compatible with the data?

a) Uranium oxide is UO and the atomic weight of U is 70

b) Uranium oxide is U3O8 and the atomic weight of U is 240

c) Uranium oxide is UO2 and the atomic weight of U is 105

d) Uranium oxide is U2O3 and the atomic weight of U is 105

88) A sample of protein was analysed for metal content and analysis revealed that if contained

magnesium and titanium in equal amounts, by weight. If these are the only metallic species

present in the protein and it contains 0.016% metal by weight, the minimum possible molar mass

of the protein is (Mg = 24, Ti = 48)

a) 600000

b) 150000

c) 300000

d) 1200000

89) A series of experiments were carried out with a fixed mass of a metal and variable mass of

chlorine. The result is represented by the adjacent graph. The empirical formula of compound

formed in each case is found to be MCl2. The atomic weight of the metal is (Cl = 35.5)

a) 40

b) 47.33

c) 118.33

d) 106.5

90) In the blood of an infant, there are about 1.3 × 1012

red blood cells, which contain a total of

about 0.15 g iron. On the average, how many iron atoms are present in each red blood cell of the

infant?

a) 8.8 × 1023

b) 4.7 × 1013

c) 1.2 × 109

d) 3.0 × 108