Question

Consider the equation: C3H8(g) + 5 O2(g) 3 CO2(g) + 4 H2O(g) + 2200 kJ.
How many grams of C3H8 must be burned to produce 19570 kJ of energy? Write your complete solution and box or highlight your final

Answer 1

The molar masses of propane and water are 44 g/mol and 18 g/mol respectively.

44.0 grams of propane corresponds to 1 mole of propane.

According to the balance chemical equation, C3H8(g)+5O2(g)→3CO2(g)+4H2O(l), 

1 mole of propane gives 4 moles of water.

Thus, the combustion of 44.0 g (1 mole) of propane will give 4 moles of water. 

Mass of water obtained =4×18=72.0 g.