## States of Matter Questions and Answers Part-1

1. 4.4 g of a gas at STP occupies a volume of 2.24 L, the gas can
a) $O_{2}$
b) CO
c) $NO_{2}$
d) $CO_{2}$

Explanation: 44g at STP occupies volume 22.4 litre which is molecular mass of CO2. Molecular mass occupies 22.4 litre at STP

2. If the four tubes of a car are filled to the same pressure with $N_{2},O_{2},H_{2} and Ne$   separately, then which one will be filled first ?
a) $N_{2}$
b) $O_{2}$
c) $H_{2}$
d) Ne

Explanation: Lesser the density more is the volume and H2 has lowest density. ( d =   $\frac{MP}{RT}$   at constant P, R and T, d   $\propto$   M )

3. When the product of pressure and volume is plotted against pressure for a given amount of the gas, the line obtained is
a) parallel to X-axis
b) parallel to Y-axis
c) linear with positive slope
d) linear with negative slope

Explanation: Plot of PV vs P at constant T is parallel to X axis.

4. Air at sea level is dense. This is a practical application of
a) Boyle’s law
b) Charle’s law
c) Kelvin’s law
d) Brown’s law

Explanation: d   $\propto$   p, Boyle’s law, d =   $\frac{MP}{RT}$   . At sea level pressure is more, hence density of air is more

5. Use of hot air balloons in sports and meteorological observations is an application of
a) Boyle’s law
b) Charle’s law
c) Kelvin’s law
d) Gay-Lussac’s law

Explanation: Hot air is lighter due to less density (Charle’s law) (d =   $\frac{MP}{RT}$   )

6. “Equal volumes of all gases at the same temperature and pressure contain equal number of particles.” This statement is a direct consequece of
a) Perfect gas law
c) Charle’s law
d) Boyle’s law

Explanation: When P, V and T are same no. of particles will also be same (Avogadro law)

7. If 300 ml of a gas at 270 C is cooled to 70 C at constant pressure, its final volume will be
a) 135 ml
b) 540 ml
c) 350 ml
d) 280 ml

Explanation: At constant pressure
$\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}} \Rightarrow \frac{300}{300}=\frac{V_{2}}{280}$     or V2 = 280 ml

8. For an ideal gas, correct relation is
a) $\left[\frac{\delta E}{\delta V}\right]_{T}=0$
b) $\left[\frac{\delta E}{\delta T}\right]_{P}=0$
c) $\left[\frac{\delta E}{\delta T}\right]_{V}=0$
d) All of these

Explanation: $\left[\frac{\delta E}{\delta V}\right]_{T}=0$     For ideal gas and positive for real gas.

9. The value of R in SI units is :
a) $8.315*10^{7}erg K^{-1}mol^{-1}$
b) $8.315 JK^{-1}mol^{-1}$
c) $0.0815 litre atm K^{-1}mol^{-1}$
d) $2 calK^{-1}mol^{-1}$

Explanation: In SI unit value of R =   $8.315 JK^{-1}mol^{-1}$
Explanation: Since for H2 and He, PV > nRT and Z =  $\frac{PV}{nRT}$ . Hence Z is more than 1