Heat Capacity at Constant Pressure

Q. The value of $\gamma =$ $\frac{C_p}{C_v}$ for hydrogen, helium and another ideal diatomic gas X, are respectively equal to:

1. $\frac{7}{5},\frac{5}{3},\frac{7}{5}$
2. $\frac{7}{5},\frac{5}{3},\frac{9}{7}$
3. $\frac{5}{3},\frac{7}{5},\frac{9}{7}$
4. $\frac{5}{3},\frac{7}{5},\frac{7}{5}$

Q.

If one mole of a polyatomic gas has two vibrational modes and β is the ratio of molar specific heats for polyatomic gas β=C_p / C_v then the value of β is.

1. 1.35

2. 1.02

3. 1.25

4. 1.2

Q. One mole of $N_2{O}_4\left(g\right)$ at 300 K is kept in a closed container under 1 atmosphere. It is heated to 600 K when $20\%$ by mass of $N_2{O}_4\left(g\right)$ decomposes to $N{O}_2\left(g\right)$. The resultant pressure is:

1. 2 atm
2. 5 atm
3. 1.2 atm
4. 2.4 atm

Q. At $0^{\circ }C$, ice and water are in equilibrium and enthalpy change for the process $H_2{O}_{\left(s\right)}\rightleftharpoons H_2{O}_{\left(l\right)}is6.0kJmo{l}^{-1}$. The entropy change for the conversion of ice into liquid water is

1. 
2. 
3. 
4. 

Q. The difference between $C_p$ and $C_v$ can be derived $H=U+PV$. Calculate the difference between $C_p$ and $C_v$ for 10 moles of an ideal gas.

1. 41.84 J/K
2. 71.48 J/K
3. 83.14 J/K
4. 23.65 J/K

Q.

The molar heat of formation of $N{H}_{4}N{O}_3\left(s\right)$ is $-367.5KJ$ and those of $N_{2}O\left(g\right)$ and $H_{2}O\left(l\right)$ are $+81.46KJ$ and $-285.78KJ$ respectively at ${25}^{o}C$ and 1 atmospheric pressure. The $△$ U for the reaction
$N{H}_{4}N{O}_3\left(s\right)\to N_{2}O\left(g\right)+2H_{2}O\left(l\right)$

1. -125.03 kJ

2. 125.03 kJ

3. 120 kJ

4. -120 kJ

Q. A sample of ideal gas $(\gamma =1.4)$ is heated at constant pressure. If an amount of $85J$ of heat is supplied to gas, find $△U$

1. $30.5J$
2. $60.7J$
3. $50.5J$
4. $70J$

Q. For a gas having molar mass $M$, specific heat at constant pressure is given by:

1. $\frac{\gamma }{RM}$
2. $\frac{M}{R(\gamma -1)}$
3. $\frac{\gamma R}{M(\gamma -1)}$
4. $\frac{\gamma RM}{(\gamma +1)}$

Q. Select the correct priority for citation as principal group.

1. $-\stackrel{O}{\stackrel{||}{C}}-OH>-\stackrel{O}{\stackrel{||}{C}}->-\stackrel{O}{\stackrel{||}{C}}-H>-OH>-SH$
2. $-\stackrel{O}{\stackrel{||}{C}}-OH>-\stackrel{O}{\stackrel{||}{C}}->-\stackrel{O}{\stackrel{||}{C}}-H>-SH>-OH$
3. $-\stackrel{O}{\stackrel{||}{C}}-OH>-\stackrel{O}{\stackrel{||}{C}}-H>-\stackrel{O}{\stackrel{||}{C}}->-SH>-OH$
4. $-\stackrel{O}{\stackrel{||}{C}}-OH>-\stackrel{O}{\stackrel{||}{C}}-H>-\stackrel{O}{\stackrel{||}{C}}->-OH>-SH$

Q. Ideal diatomic gas is taken through a process, $Q=2\Delta U$. Find the molar heat capacity for the process (where $Q$ is the heat supplied and $\Delta U$ is the change in thermal energy).

Q. 2 mole $He$ is mixed with 2 g of $H_2$. The molar heat capacity at constant pressure for the mixture is:

1. $\frac{11R}{6}$
2. $4R$
3. $\frac{3R}{2}$
4. $\frac{17R}{6}$

Q. 17. The reaction which is not occurring at the temperature range of 500 to 800 K in blast furnace ?

Q. Determine the heat energy needed to increase the temperature of $5mol$ of mercury by $10K$. The value of heat capacity for given amount of mercury is $27.8J{K}^{-1}$

1. $278J$
2. $2085J$
3. $208.5J$
4. $2780J$

Q. The difference between $C_p$ and $C_v$ can be derived using $H=U+PV$. Calculate the difference between $C_p$ and $C_v$ for 10 moles of an ideal gas.

1. 41.84 J/K
2. 71.48 J/K
3. 23.65 J/K
4. 83.14 J/K

Q. The molar heat capacity of water in equilibrium with ice at constant pressure is

1. Zero

2. Infinity

3. 40.45 kJ^-1 K^-1

4. 75.48 J K^-1 mol^-1

Q.

What mass of a solid with the specific heat capacity of 0.75 Jg^-1 °C^-1 will have the heat capacity of 93.75 Jg^-1 °C^-1?

Q.

Are noble gases reactive ?

Q.

The amount of heat required to raise the temperature of $1\mathrm{g}$of water through $1°\mathrm{C}$ is called

1. latent heat of vaporization

2. specific heat capacity

3. $1\mathrm{calorie}/\mathrm{g}°\mathrm{c}$

4. $540\mathrm{calorie}/\mathrm{g}$

Q. $2.2$ g of a compound of phosphorous and sulphur has $1.24$ g of $P$ in it. Its empirical formula is :

1. $P_2{S}_3$
2. $P_3{S}_2$
3. $P_4{S}_3$
4. $P_3{S}_4$

Q. The temperature of $20$ litres of nitrogen was increased from $100K$ to $300K$ at a constant pressure. Change in volume will be

1. $80$ litres
2. $60$ litres
3. $40$ litres
4. $20$ litres

Q. The specific heat at constant volume for a gas is 0.075 cal/g and at constant pressure is 0.125 cal/g. Calculate: (a) the molar mass of gas (b) atomicity of gas (c) no. of atoms, if gas in its 1 mole.

1. $a\left)40b\right)1.66c)6.023\times {10}^{23}$
2. $a\left)40b\right)1.66c)=5.023\times {10}^{22}$
3. $a\left)30b\right)0.66c)6.023\times {10}^{23}$
4. None of these

Q. Heat of reaction for; $CO\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\to {CO}_2\left(g\right)$ at constant V is $-67.71$ cal ${17}^{o}C$. The heat of reaction at constant P at ${17}^{o}C$:

1. $-68.0Kcal$
2. $+68.0Kcal$
3. $-67.42Kcal$
4. None of these

Q. We can show that for a reaction taking place at constant pressure,
$\frac{d\Delta H}{dT}={\Delta C}_p$

Q. The molar heat capacity $\left(C_p\right)$ of water at constant pressure is $75J{K}^{-1}{mol}^{-1}$. The increase in temperature (in $K$) of $100g$ of water when $1kJ$ of heat is supplied to it is:

1. $2.4$
2. $0.24$
3. $1.3$
4. $0.13$

Q. A sample of ideal gas $(\gamma =1.4)$ is heated at constant pressure. If an amount of $85J$ of heat is supplied to gas, find $△U$ (In joule).

Q. The heat of reaction for $C_{10}{H}_8\left(s\right)+12O_2\left(g\right)\to 10C{O}_2\left(g\right)+4H_{2}O\left(l\right)$ at constant volume is (1229.892 Kcal at ${25}^0$C. Calculate the heat of reaction at constant pressure at ${25}^0$C.

1. 1231.084 Kcal
2. 1992.367 Kcal
3. 5671.315 Kcal
4. 2234.567 Kcal

Q.

Q. A sample of ideal gas $(\gamma =1.4)$ is heated at constant pressure. If an amount of $85J$ of heat is supplied to gas, find $△U$

1. $30.5J$
2. $60.7J$
3. $50.5J$
4. $70J$

Q. An ideal gas has a specific heat at constant pressure to be $C_p=\frac{5}{2}R$. The gas is kept in a closed vessel of volume $0.0083m^3$ at a temperature of $300K$ and a pressure of $1.6\times {10}^{6}N/m^2$. An amount of $2.49\times {10}^{4}J$ of heat energy is supplied to the gas. Calculate the final temperature and pressure of the gas. Give $R=8.3J/mo{l}^{-1}{K}^{-1}$.

1. $T_2=675K$, $P_2=1.8\times {10}^{6}N/m^2$
2. $T_3=65K$, $P_2=1.8\times {10}^{6}N/m^2$
3. $T_2=675K$, $P_2=3.6\times {10}^{6}N/m^2$
4. $T_3=65K$, $P_2=3.6\times {10}^{6}N/m^2$

Q. What is the value of change in internal energy at $1$ atm in the process?
$H_{2}O(l,323K)⟶H_{2}O(g,423K)$

1. $42.91kJ/mol$
2. $43086kJ/mol$
3. $42.6kJ/mol$
4. $49.6kJ/mol$