Question

Propane (c3h8) is burned in oxygen to produce carbon dioxide and water. the heat of combustion of propane is -2012 kj/mole. how much heat is given off when 3.0 mol c3h8 are reacted with 10.0 mol o2? 1. 672 kj 2. 6036 kj 3. 2012 kj 4. 4024 kj 5. 1555 kj 6. 7392 kj

Answer 1

$C_{3} H_{8} + 5 O_{2} ---\ \textgreater \ 3CO_{2} +4H_{2}O (-2012 \frac{kJ}{mol} ) 3 mol 10 mol C_{3}H_{8} is /excess /reactant because 3 mol propane require 15 mol oxygen (by reaction) 5 mol oxygen ---1 mol propane, so 10 mol oxygen ---2 mol propane Only 2 mole propane will be burned, so 2012 ( kJ/mol)*2 mol =4024 KJ heat will be given off Correct answer is number 4.$