Question

1.A bomb calorimeter, or a constant volume calorimeter, is a device often used to determine the heat of combustion of fuels and the energy content of foods. In an experiment, a 0.3807 g sample of 1,6-hexanediol (C6H14O2) is burned completely in a bomb calorimeter. The calorimeter is surrounded by 1.139×103 g of water. During the combustion the temperature increases from 25.30 to 27.59 °C. The heat capacity of water is 4.184 J g-1°C-1. The heat capacity of the calorimeter was determined in a previous experiment to be 760.0 J/°C. Assuming that no energy is lost to the surroundings, calculate the molar heat of combustion of 1,6-hexanediol based on these data. C6H14O2(s) + (17/2) O2(g) 7 H2O(l) + 6 CO2(g) + Energy Molar Heat of Combustion = ? kJ/mol

Answer 1

Assuming that no energy is lost to the surrounding. Here we only need the weight of sample,heat capacity of bomb calorimeter,initial and final temperatures.

Given:

mass of 1,6 - hexanediol (C₆H₁₄O₂) = 0.3807g

Molecular weight of 1,6- hexanediol (C₆H₁₄O₂) = 118 g/mol

T_final = 27.59

T_initial = 25.30

Heat Capacity of Calorimeter =

The heat generated in calorimeter is calculated by the formula as,

  

Substituting the values,

We know that, heat of reaction i.e, in this case heat of combustion is negative of the thermal energy gained by calorimeter and its contents through combustion reaction.

  

  

Here we want the molar heat of cumbustion.

.....ans