Measurement of ??U and ??H — Prelims Questions

A $0.5\text{ g}$ sample of a solid fuel is combusted in a bomb calorimeter. The temperature of the calorimeter increases by $2.8\text{ \textdegree C}$. If the heat capacity of the calorimeter is $9.5\text{ kJ/\textdegree C}$, what is the change in internal energy ($\Delta U$) for the combustion of this $0.5\text{ g}$ sample?

For the reaction $N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)$ at $27\text{ \textdegree C}$, if $\Delta H = -92.4\text{ kJ}$, what is the value of $\Delta U$? (Given $R = 8.314\text{ J/mol\cdot K}$)

Which of the following statements is TRUE regarding the measurement of $\Delta H$ using a coffee-cup calorimeter?

When $100\text{ mL}$ of $0.2\text{ M AgNO}_3$ solution is mixed with $100\text{ mL}$ of $0.2\text{ M HCl}$ solution in a coffee-cup calorimeter, the temperature of the mixture increases by $1.5\text{ \textdegree C}$. Assuming the density of the final solution is $1.0\text{ g/mL}$ and its specific heat capacity is $4.18\text{ J/g\cdot \textdegree C}$, calculate the heat of reaction ($q_{reaction}$) in Joules.

For which of the following reactions would $\Delta H$ be approximately equal to $\Delta U$?

A bomb calorimeter experiment determined that the combustion of $1.0\text{ mol}$ of glucose ($C_6H_{12}O_6(s)$) at $298\text{ K}$ released $2808\text{ kJ}$ of heat. The balanced combustion reaction is $C_6H_{12}O_6(s) + 6O_2(g) \rightarrow 6CO_2(g) + 6H_2O(l)$. What is the molar enthalpy change ($\Delta H$) for this reaction at $298\text{ K}$? (Given $R = 8.314\text{ J/mol\cdot K}$)

Which of the following conditions is essential for the direct measurement of $\Delta H$ using a calorimeter?