Question

13. Butane, C.Ho, is the fuel used in many hand-held lighters (see Figure 8.16). Based on the reaction enthalpy below, how many grams of butane are needed to produce 1,000 kJ of heat by this reaction? 2 C.H. (g) + 13 O, (o) → 8 CO2(g) + 10 HOU AH = -5,755 kJ

Answer 1

when -5755.0 KJ of heat is involved, 2 mol of C4H10 is reacting

So,

for -1*10^3 KJ, mol of C4H10 = -1*10^3*2/-5755.0 KJ

= 0.3475 mol

Molar mass of C4H10,

MM = 4*MM(C) + 10*MM(H)

= 4*12.01 + 10*1.008

= 58.12 g/mol

use:

mass of C4H10,

m = number of mol * molar mass

= 0.3475 mol * 58.12 g/mol

= 20.2 g

Answer: 20.2 g