A0.468 g sample of pentane, c 5h 12, was burned in a bomb calorimeter. the temperature of the calorimeter and 1.00 kg of water in it rose from 20.45 °c to 23.65 °c. the heat capacity of the calorimeter by itself is 2.21 kj/°c and the specific heat capacity of water is 4.184 j/g.°c what is the heat of combustion per mole of pentane?

per mole of pentane = 3157.53 kJ/mol

Explanation:

Given:

Mass of pentane, m = 0.468 gram

Molar mass of pentane, M = 72.15

Now, mol of pentane, n = mass/M = 0.468/72.15 = 0.00648 mol of C5H12

Now,

ΔT = 23.65 - 20.45 = 3.2°C

Heat capacity of the calorimeter, C = 2.21 kJ/°C

Specific heat capacity of the water, Cp = 4.184  J/g.°C

Now,

the heat gained = the heat lost

also,

or

and

Now,

we have,

(Here negative sign depicts the release of the heat)

per mole of pentane =-20460.8/(0.00648 ) = 3157.53 kJ/mol

that would be because of both gravity and friction. so     c