ques 14 HW8 The following equation is the balanced combustio

ques 14 HW8

The following equation is the balanced combustion reaction for C6H6:

2C6H6(l) +1502(g) ----> 12CO2(g)+6H2O(l)+6542 kj

If 6.300 g of C6H6 is burned and the heat produced from the burning is added to 5691 g of water at 21 °C, what is the final temperature of the water?

Solution

C6H12 = 6x12 + 6x1 = 78.
The equation indicates that 2x78 = 156g benzene will produce 6542kJ.
Using proportions you can then calculate that
x/6542kJ = 6.3g / 156g
x = 264.2kJ = 264201J.

heat = mass x T x 4.18J/g°
T = 264201J / (5691g x 4.18J/g°) = 11.1°

final temp = 21 + 11.1° = 32.1°C