Question

What volume of benzene (C6H6, d=0.88g/ml, molar mass =78.11g/mol) is required to produce 1.5•10*3kj of heat according to the following rxn?:

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

delta H rxn= -6278kj

Answer 1

when -6278.0 KJ of heat is involved, 2 mol of C6H6 is reacting

So,

for -1.5*10^3 KJ, mol of C6H6 = -1.5*10^3*2/-6278.0 KJ

= 0.4779 mol

Molar mass of C6H6 = 78.11 g/mol

use:

mass of C6H6,

m = number of mol * molar mass

= 0.4779 mol * 78.11 g/mol

= 37.32 g

Now use:

Volume = mass / density

= 37.32 g / 0.88 g/mL

= 42.41 mL

Answer: 42.4 mL