List of practice Questions

Enthalpies of formation of CO(g), CO₂(g), N₂O(g) and N₂O₄(g) are –110, – 393, 81 and 9.7 kJ mol^-1 respectively. Find the value of ∆_rH for the reaction.
\(N_2O_4(g) + 3CO(g) → N_2O(g) + 3CO_2(g)\)

Calculate the enthalpy change on freezing of \(1.0\ mol\) of water at \(10.0°C\) to ice at \(-10.0°C\). \(∆_{fus}H = 6.03\ kJ mol^{–1}\) at \(0°C\).
\(C_p [H_2O(l)] = 75.3\ J mol^{–1}K^{–1}\)
\(C_p [H_2O(s)] = 36.8 \ J mol^{–1}K^{–1}\)

Enthalpy of combustion of carbon to CO₂ is –393.5 kJ mol^–1. Calculate the heat released upon formation of 35.2 g of CO₂ from carbon and dioxygen gas.

Given, \(N_2(g) + 3H_2(g)→2NH_3(g)\); \(∆_rH^Θ=-92.4\ kJ mol^{–1}\)
What is the standard enthalpy of formation of \(NH_3\) gas?

Calculate the standard enthalpy of formation of \(CH_3OH(l)\) from the following data.
\(CH_3OH (l) +\frac 32 O_2(g)→CO_2(g)+2H_2O (l)\) ;  \( ∆_rH^Θ= –726 \ kJ mol^{–1}\),
\(C(graphite)+O_2(g)→CO_2(g)\);  \(∆_cH^Θ = –393 \ kJ mol^{–1}\),
\(H_2(g)+\frac 12 O_2(g)→H_2O (l)\);  \(∆_f H^Θ= –286 kJ mol^{–1}\)

Calculate the enthalpy change for the process
\(CCl_4(g) → C(g) + 4Cl(g)\)
and calculate bond enthalpy of \(C-Cl\) in \(CCl_4(g)\).
\(∆_{vap}H^Θ(CCl_4) = 30.5\ kJ mol^{-1}\).
\(∆_fH^Θ(CCl_4)= –135.5\ kJ mol^{-1}\).
\(∆_aH^Θ (C)= 715.0\ kJ mol^{-1}\),    where \(∆_aH^Θ\) is enthalpy of atomisation.
\(∆_aH^Θ (Cl_2) = 242\ kJ mol^{-1}\).

For an isolated system, ∆U=0, what will be ∆S ?

The equilibrium constant for a reaction is \(10\). What will be the value of \(∆G^Θ\)?
\(R= 8.314\ JK^{-1} mol^{-1}, T=300\ K\)