Question
The symbol equation for combustion of a hydrocarbon is shown below.. What number should go before the water product in order to balance this equation? Enter your answer as a number C_(3)H_(8)+ldots O_(2)arrow ldots CO_(2)+ldots H_(2)O
Answer
4.1
(155 Votes)
Xenia
Expert · Tutor for 3 years
Answer
4
Explanation
A chemical equation balances when the number of atoms for each element in the reactants side equals the number of atoms for each element on the products side. The chemical equation shows the combustion of propane, C3H8, becoming carbon dioxide (CO2) and water (H2O). To find how many H2O molecules are needed, we must balance the hydrogen atoms first. There are 8 hydrogen atoms in C3H8, which on the right side are each part of an H2O molecule. Because each molecule of water consists of 2 hydrogen atoms, you will need 4 H2O molecules in order to have 8 hydrogen atoms, balancing the equation.