A bomb calorimeter (C = 147 J/°C) contained 65 g of C4H4O (l) and excess O2 (g).

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 E 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?

Explanation / Answer

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

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