Question

The balanced combustion reaction for C6H6 is

2C₆H₆(l)+15O₂(g) --> 12CO₂(g)+6H₂O(l)+6542kJ

If 8.000 g C₆H₆ is burned and the heat produced from the burning is added to 5692 g of water at 21 C, what is the final temperature of the water?

final temperature: _________________ C

Answer 1

no of moles of C6H6   = W/G.M.Wt

                                      = 8/78   = 0.1026mole

2C₆H₆(l)+15O₂(g) --> 12CO₂(g)+6H₂O(l)+6542kJ

$\Delta$H   = -6542KJ

2 mole of C6H6 combustion to release energy is -6542KJ

0.1026 moles of C6H6 combustion to release energy = -6542*0.1026/2   = -335.6046KJ

q   = $\Delta$ H = -335.6046KJ =- 335604.6J

m = 5692g

t1 = 21⁰C

q = mc$\Delta$T

335604.6 = 5692*4.184*(t-21)

t = 35.1⁰C

The final temperature of water = 35.1⁰C >>>.answer