Consider the following reaction: CH4(g) + 2O2(g) ↓ CO2 (g) + 2H2O(g) One molecule of methane (CH4) reacts with two molecules of oxygen to form one molecule of carbon dioxide and two molecules of water.
1. If 36 water molecules are formed from the above reaction, how many methane molecules reacted?
2. If 54 water molecules are formed by the above reaction, how many carbon dioxide molecules formed?
CH4 : H2O = 1:2
CO2 : H2O = 1:2
To answer these questions, we need to use the stoichiometry of the reaction, which relates the number of molecules of each species involved in the reaction.
1. If 36 water molecules are formed, we want to find the number of methane molecules that reacted.
From the balanced equation, we can see that 1 molecule of methane (CH4) reacts to form 2 molecules of water (H2O). Therefore, for every 2 molecules of water formed, 1 molecule of methane reacts.
To find the number of methane molecules reacting, we divide the number of water molecules formed by 2:
Number of methane molecules = Number of water molecules / 2
Number of methane molecules = 36 / 2 = 18
Therefore, 18 methane molecules reacted.
2. If 54 water molecules are formed, we want to find the number of carbon dioxide molecules formed.
From the balanced equation, we can see that 1 molecule of methane (CH4) reacts to form 1 molecule of carbon dioxide (CO2). Therefore, the number of carbon dioxide molecules formed is equal to the number of methane molecules that reacted.
To find the number of carbon dioxide molecules formed, we use the same number of methane molecules found in question 1:
Number of carbon dioxide molecules = Number of methane molecules = 18
Therefore, 18 carbon dioxide molecules formed.