To determine the number of moles of water produced when 7 moles of hydrogen gas react with 3 moles of oxygen gas in the given chemical equation 2H2 + O2 → 2H2O, we need to consider the balanced chemical equation.
1. **Balanced Chemical Equation**:
- 2 moles of hydrogen gas (H2) react with 1 mole of oxygen gas (O2) to produce 2 moles of water (H2O).
2. **Given Reactants**:
- Hydrogen gas (H2): 7 moles
- Oxygen gas (O2): 3 moles
3. **Stoichiometry**:
- From the balanced equation, we can see that 2 moles of hydrogen gas (H2) are required to produce 2 moles of water (H2O).
- Since the ratio is 1:1 for hydrogen gas and water, the number of moles of water produced will be equal to the number of moles of hydrogen gas consumed.
4. **Calculation**:
- When 7 moles of hydrogen gas react, they will produce 7 moles of water.
Therefore, when 7 moles of hydrogen gas react with 3 moles of oxygen gas, 7 moles of water are produced.
