A laboratory setup uses the combustion of propane to heat of water from to

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

A laboratory setup uses the combustion of propane to heat

500\,\text{g}

of water from

25^{\circ}\text{C}

80^{\circ}\text{C}

. Assume no heat is lost to the surroundings. The specific heat capacity of water is

4.18\,\text{J}\,\text{g}^{-1}\,^{\circ}\text{C}^{-1}

and the molar enthalpy of combustion of propane is

\Delta H_{\text{rxn}} = -2.22\times10^{3}\,\text{kJ}\,\text{mol}^{-1}

. What mass of propane (C

_3

_8

) must be burned? (a)

5.7\ \text{g}

(b)

0.23\ \text{g}

(c)

2.3\ \text{g}

(d)

3.3\ \text{g}