Question

A bomb calorimeter (C = 147 J/°C) contained 65 g of C4H4O (l) and excess O2 (g). The calorimeter was immersed in a 150. g water bath (Cwater = 4.19 J/g°C) and the calorimeter and the bath were equilibrated at 22.00 °C. The fuel was combusted, and the temperature of the calorimeter and the water bath were monitored independently. After 5 minutes, the calorimeter reached a maximum temperature of 25.04°C. At that time, the water bath had warmed to 22.62 °C.

a. Write the balanced reaction for the combustion of C4H4O (l).
b. Based on the data provided, estimate ΔE for the combustion of C4H4O (l).

c. Over time, the calorimeter and the water bath will come to a common final temperature (thermal equilibrium). Assuming no heat is lost to the environment, what is the final temperature reached by the calorimeter and the water bath?

Answer 1

The balanced reaction is

a) C4H4O+4.5O2----> 4CO2+2H2O

b) Heat gained by calorimeter= C* temperature difference= 147*(25.04-22.00)=446.88 joules

Heat gained by water= mass* specific heat of water* temperature differenc= 150*4.18*(22.62-22)=388.74 joules

delE of combustion of C4H4O= heat gained by calorimeter + heat gained by water= 446.88+388.74=835.62 joules

c)

c) heat of combustion of Furan = 30 KJ/mole= 30000j/mole

mass of C4H4O= 65 gm molecular weight = (4*12+4+16)= 68

Moles of C4H4O= 65/68=0.96

1 moles produces =30000 joules

0.96 moles produces 30000*0.96=28800 joules

Let the final temperature be T

heat gained by calorimeter + heat gained by water= enthalpy change of combustion

147*(T-22)+150*4.19*(T-22)= 28800

775.5*(T-22)= 28800

T-22= 37.13

T= 37.13+22= 59.13 deg.c