As a result of the reaction between oxygen and hydrogen, water with a volume of 9 cm3

As a result of the reaction between oxygen and hydrogen, water with a volume of 9 cm3 was formed, find the volumes of the gases that reacted.

Decision:
1. Let’s write the equation for the reaction of the interaction of oxygen and hydrogen with spaced coefficients:
2H2 + O2 = 2H2O;
2. The density of water is 1000 kg / m3. In other units, this value is 1 g / cm3.
3. Find the mass of the resulting water:
9 * 1 = 9 grams
4. The molar mass of water is 18 g / mol.
5. Let’s find the amount of substance in 9 cm3 of water:
9/18 = 0.5 mol
6. The molar volume of gases is 22.4 l / mol.
7. There is the same coefficient in front of hydrogen as in front of water. This means that the amount of substance in hydrogen will be 0.5 mol. Let’s find the volume of hydrogen:
22.4 * 0.5 = 11.2 liters
8. Oxygen is preceded by a coefficient two 2 less than that of water. The amount of substance in oxygen will be 2 times less, namely 0.25 mol. Let’s find the volume of oxygen:
22.4 * 0.25 = 5.6 liters
Answer: the volume of hydrogen is 11.2 liters, the volume of oxygen is 5.6 liters.