States of Matter Questions and Answers Part-4

1. The compressibility factor for an ideal gas is
a) 1.5
b) 1.0
c) 2.0
d) \[\propto\]

  Discussion

Answer: b
Explanation: Ideal gas strictly follows PV= nRT, Z = \[\frac{PV}{nRT} \] = 1

2. A gas will approach ideal behaviour at
a) low temperature and low pressure
b) low temperature and high pressure
c) high temperature and low pressure
d) high temperature and high pressure

  Discussion

Answer: c
Explanation: Ideal behaviour at low P and high temperature. The larger the volume the lesser are the interactions, higher the temperature the more is KE the lesser are interactions between the molecules.

3. The compressibility of a gas is less than unity at STP. Therefore
a) \[V_{m}>22.4 litres\]
b) \[V_{m}<22.4 litres\]
c) \[V_{m}=22.4 litres\]
d) \[V_{m}=44.8 litres\]

  Discussion

Answer: b
Explanation: Z = \[\frac{PV}{nRT} \] < 1
nRT > PV
1*0.0821*273 > 1*V or V < 22.4

4. An ideal gas will have maximum density when
a) P = 0.5 atm, T = 600 K
b) P = 2 atm, T = 150 K
c) P = 1 atm, T = 300 K
d) P = 1 atm, T = 500 K

  Discussion

Answer: b
Explanation: Higher P lower T greater the density

5. 120 g of an ideal gas of molecular weight \[40 g mol^{-1}\] are confined to a volume of 20 L at 400 K. Using R=0.0821 L atm \[K^{-1}mol^{-1}\] , the pressure of the gas is
a) 4.90 atm
b) 4.92 atm
c) 5.02 atm
d) 4.96 atm

  Discussion

Answer: b
Explanation:
q35

6. The volume of 0.0168 mol of \[O_{2}\] obtained by decomposition of \[KClO_{3}\] and collected by displacement of water is 428 ml at a pressure of 754 mm Hg at 250 C. The pressure of water vapour at 250 C is
a) 18 mm Hg
b) 20 mm Hg
c) 22 mm Hg
d) 24 mm Hg

  Discussion

Answer: d
Explanation:
q36

7. Pressure of a mixture of 4 g of \[O_{2}\] and 2 g of \[H_{2}\] confined in a bulb of 1 litre at 00 C is
a) 25.215 atm
b) 31.205 atm
c) 45.215 atm
d) 15.210 atm

  Discussion

Answer: a
Explanation:
q37

8. Same mass of \[CH_{4}and H_{2}\]   is taken in container, The partial pressure caused by \[H_{2}\] is
a) \[\frac{8}{9}\]
b) \[\frac{1}{9}\]
c) \[\frac{1}{2}\]
d) 1

  Discussion

Answer: a
Explanation:
q38

9. There are \[6.02* 10^{22}\]   molecules each of \[N_{2},O_{2} andH_{2}\]   which are mixed together at 760 mm and 273 K. The mass of the mixture in grams is
a) 6.02
b) 4.12
c) 3.09
d) 6.2

  Discussion

Answer: d
Explanation:
q39

10. The density of air is 0.00130 g/ml. The vapour density of air will be
a) 0.00065
b) 0.65
c) 14.4816
d) 14.56

  Discussion

Answer: d
Explanation: VD of air = mass of 11200cc of air = 11200 × density of air = 11200 × .00130 = 14.56