Question

On combustion of x-g of ethanol in a bomb calorimeter, y-joules of heat energy is produced. The heat of combustion of ethanol (\(\Delta H_{{comb}}\)) is

• A. \(\Delta H_{{comb}} = -x \cdot J\)
• B. \(\Delta H_{{comb}} = -yJ\)
• C. \(\Delta H_{{comb}} = - \frac{x}{y} \times 44 \, {J mol}^{-1}\)
• D. \(\Delta H_{{comb}} = - \frac{y}{x} \times 44 \, {J mol}^{-1}\)

Hint:

Remember, the heat of combustion per gram can be converted into energy per mole using the molar mass of ethanol.

Answer 1

The Correct Option is D

The heat of combustion of ethanol is given by the formula: \[ \Delta H_{{comb}} = - \frac{y}{x} \times 44 \, {J mol}^{-1} \] Where: - \( x \) is the mass of ethanol in grams - \( y \) is the energy released in joules - The standard heat of combustion for ethanol is \( 44 \, {J mol}^{-1} \) Thus, option (d) is the correct answer.