Applications of Thermodynamics: Enthalpy

The quantity of heat (in $J$) required to raise the temperature of $1.0\mathit{ }kg$ of ethanol from $293.45 K$ to the boiling point and then change the liquid to vapor at that temperature is closest to [Given, boiling point of ethanol $351.45 K$. Specific heat capacity of liquid ethanol $2.44\mathit{ }J\mathit{ }{g}^{-1} K^{-1}$. Latent heat of vaporisation of ethanol $855 J{g}^{-1}$ ]

The difference between $\mathrm{Cp}$ and $\mathrm{Cv}$ for liquids and solids is extremely large.

Matching Type question

One mol of a non-ideal gas undergoes a change of state $(2.0 \mathrm{atm}, 3.0 \mathrm{L}, 95 \mathrm{K}) \to (4.0 \mathrm{atm}, 5.0 \mathrm{L}, 245 \mathrm{K})$ with a change in internal energy, $∆\mathrm{U}$$= 30.0 \mathrm{L} \mathrm{atm}$. The change in enthalpy $(∆\mathrm{H})$ of the process in $\mathrm{L} \mathrm{atm}$ is

Molar heat capacity of aluminium is $25$ $\mathrm{J} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}$. The heat necessary to raise the temperature of $54 \mathrm{g}$ of aluminium (Atomic mass $27 \mathrm{g} {\mathrm{mol}}^{-1}$ ) from $30 °\mathrm{C}$ to $50°\mathrm{C}$ is

How much energy does it take to raise the temperature of $50 \mathrm{g}$ of copper by $100°\mathrm{C}$? The specific heat capacity of copper is $0.4 \mathrm{J} {\mathrm{g}}^{-1} °{\mathrm{C}}^{-1}$.

Heat capacity of an iron pin will be different from a big iron brick.

In a constant volume calorimeter, $\text{3.5 g}$ of a gas with molecular weight $\text{28}$ was burnt in excess oxygen at $\text{298.0 K}$. The temperature of the calorimeter was found to increase from $\text{298.0 K}$ to $\text{298.45 K}$ due to the combustion process. Given that heat capacity of the calorimeter is $\text{2.5 kJ}{\text{ K}}^{-1}$, the numerical value for the enthalpy of combustion of the gas in $\text{kJ}{\text{ mol}}^{-1}$ is

For a perfect gas

$C_P/C_V$ for noble gases is

For the reaction: ${\mathrm{N}}_2+3{\mathrm{H}}_2\mathrm{ }\rightleftharpoons 2\mathrm{N}{\mathrm{H}}_3$

Which one of the following is correct regarding $∆\mathrm{H}?$

250 ml of 0.1 MHCl and 250 ml of 0.1 MKOH, both being at the same temperature, are mixed thoroughly and the temperature rise is found to be $∆T_1.$ If the experiment is repeated using 500 ml each of the two solutions and $∆T_2$ is the temperature rise, then which is true?

Statement = $C_P-C_V=R$ for an ideal gas

Explanation $={\left(\frac{\partial U}{\partial V}\right)}_T=0$ for an ideal gas.

For an ideal gas, $\frac{{\mathrm{C}}_{\mathrm{p},\mathrm{m}}}{{\mathrm{C}}_{\mathrm{v},\mathrm{m}}}=\mathrm{\gamma }$. The molecular mass of a gas is $\mathrm{M}$, its specific heat capacity at constant volume is:

Stearic acid $\left[\mathrm{C}{\mathrm{H}}_3{\left(\mathrm{C}{\mathrm{H}}_2\right)}_{16}\mathrm{C}{\mathrm{O}}_2\mathrm{H}\right]$ is a fatty acid, the part of fat that stores most of the energy. 1.0 g of stearic acid was burnt in a bomb calo rimeter. The bomb had a heat capacity of $652\mathrm{ }\mathrm{J}/{}^{\mathrm{o}}\mathrm{C}\mathrm{ }$ . If the temperature of 500 g water $\left(\mathrm{c}=4.18\mathrm{ }\mathrm{J}/\mathrm{g}{}^{\mathrm{o}}\mathrm{C}\right)$ rose from 25.0 to ${39.3}^{\mathrm{o}}\mathrm{C}$ , how much heat was released when the stearic acid was burnt? [Given ${\mathrm{C}}_{\mathrm{p}}\left({\mathrm{H}}_2\mathrm{O}\right)=4.18\mathrm{ }\mathrm{J}/\mathrm{g}{}^{\mathrm{o}}\mathrm{C}$ ]

Diborane is a potential rocket fuel which undergoes combustion according to the reaction,

${\mathrm{B}}_2{\mathrm{H}}_{6\left(\mathrm{g}\right)}+3{\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{B}}_2{\mathrm{O}}_{3\left(\mathrm{g}\right)}+3{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{g}\right)}$

From the following data, calculate the enthalpy change for the combustion of diborane :

$\left(\mathrm{i}\right)\mathrm{ }2{\mathrm{B}}_{\left(\mathrm{s}\right)}+\left(\frac{3}{2}\right){\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{B}}_2{\mathrm{O}}_{3\left(\mathrm{s}\right)}\mathrm{ };\mathrm{\Delta }\mathrm{H}=\mathrm{ }-1273\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$

$\left(\mathrm{i}\mathrm{i}\right){\mathrm{ }\mathrm{H}}_{2\left(\mathrm{g}\right)}+\left(\frac{1}{2}\right){\mathrm{O}}_{2\left(\mathrm{g}\right)}\to {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\mathrm{ };\mathrm{\Delta }\mathrm{H}=\mathrm{ }-286\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$

$\left(\mathrm{i}\mathrm{i}\mathrm{i}\right)\mathrm{ }{\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)}\to {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{g}\right)}\mathrm{ };\mathrm{\Delta }\mathrm{H}=44\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$

$\left(\mathrm{i}\mathrm{v}\right)\mathrm{ }2{\mathrm{B}}_{\left(\mathrm{s}\right)}+3{{\mathrm{H}}_2}_{\left(\mathrm{g}\right)}\to {\mathrm{B}}_2{\mathrm{H}}_{6\left(\mathrm{g}\right)}\mathrm{ };\mathrm{\Delta }\mathrm{H}=36\mathrm{ }\mathrm{kJ}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$

Which statement (s) is/ are correct?

For two mole of an ideal gas:

Molar heat capacity at constant P for a substance is equal to:

If for an ideal gas, the ratio of pressure and volume is constant and is equal to $1\mathrm{ }\mathrm{a}\mathrm{t}\mathrm{m}\mathrm{ }\mathrm{L}{-}^1$, the molar heat capacity at constant pressure would be: