Stoichiometry MCQs

Question 1

The quantity of heat required to evaporate 1 kg of a saturated liquid is called

Accepted Answer

Latent heat

Answer

Specific heat

Answer

1 Kcal

Answer

Sensible heat

Question 2

Raoult's law states that 'the equilibrium vapor pressure that is exerted by a component in a solution is proportional to the mole fraction of that component'. This generalisation is based on the assumption that the

Accepted Answer

All of the above

Answer

Sizes of the component molecules are approximately equal

Answer

Attractive forces between like and unlike molecules are approximately equal

Answer

Component molecules are non-polar and no chemical combination or molecular association between unlike molecules takes place in the formation of the solution

Question 3

Density of carbon dioxide is __________ kg/Nm 3 .

Accepted Answer

44/22.4

Answer

44/22400

Answer

22.4/44

Answer

None of these

Question 4

With rise in temperature, the heat capacity of a substance

Accepted Answer

Increases

Answer

Decreases

Answer

Remains unchanged

Answer

Either A or B; depends on the substance

Question 5

A gaseous mixture contains 14 kg of N 2 , 16 kg of O 2 and 17 kg of NH 3 . The mole fraction of oxygen is

Accepted Answer

0.33

Answer

0.16

Answer

0.66

Answer

0.47

Question 6

Pick out the wrong statement.

Accepted Answer

Generally, the heat capacities of compounds are lower in the liquid than in the solid state

Answer

Atomic heat capacities of the crystalline solid elements are nearly constant and equal to 6.2 kcal/kg-atom according to the law of Petit and Dulong

Answer

Atomic heat capacities of all solid elements decrease greatly with decrease in temperature, approaching a value of zero at absolute zero temperature, when in the crystalline state

Answer

The heat capacity of a heterogeneous mixture is an additive property, but when solutions are formed, this additive property may no longer exist

Question 7

The molecular velocity of a real gas is proportional to (where, T = absolute temperature of the gas).

Accepted Answer

$$\sqrt {	ext{T}} $$

Answer

T

Answer

T 2

Answer

$$\frac{1}{{\sqrt {	ext{T}} }}$$

Question 8

An equation for calculating vapour pressure is given by, log 10 P = A - B(t + c). This is called the

Accepted Answer

Antonic equation

Answer

Kistyakowsky equation

Answer

Kopp's rule

Answer

Trouton's rule

Question 9

The heats of vaporisation of CS 2 , C 2 H 5 OH & H 2 O are 26.8, 38.6 & 40.6 KJ/kg mole respectively. The order of decreasing inter-molecular forces in these liquids is

Accepted Answer

H 2 O > C 2 H 5 OH > CS 2

Answer

CS 2 > C 2 H 5 OH > H 2 O

Answer

H 2 O > CS 2 > C 2 H 5 OH

Answer

CS 2 > H 2 O > C 2 H 5 OH