To determine the mass of hydrogen gas (H₂) that participates in the chemical reaction, we need to use the molar mass of hydrogen gas and the given moles.
1. **Determine the molar mass of H₂:**
- Hydrogen (H) has an atomic mass of approximately 1.008 g/mol.
- Since H₂ contains 2 hydrogen atoms, the molar mass of H₂ is:
\[
\text{Molar mass of H₂} = 2 \times 1.008 \, \text{g/mol} = 2.016 \, \text{g/mol}
\]
2. **Calculate the mass of H₂ gas:**
- Use the formula:
\[
\text{mass} = \text{moles} \times \text{molar mass}
\]
- Substitute the given values:
\[
\text{mass} = 0.075 \, \text{moles} \times 2.016 \, \text{g/mol}
\]
3. **Perform the multiplication:**
\[
\text{mass} = 0.075 \times 2.016 = 0.1512 \, \text{g}
\]
4. **Determine the correct number of significant digits:**
- The given value (0.075 moles) has 2 significant digits.
- Therefore, the result should also be reported with 2 significant digits.
5. **Round the result to 2 significant digits:**
\[
\text{mass} \approx 0.15 \, \text{g}
\]
So, the mass of hydrogen gas that participates in the reaction is **0.15 grams**.
A chemist determines by measurements that 0.075 moles of hydrogen gas participate in a chemical reaction. Calculate the mass of hydrogen gas that participates.
Be sure your answer has the correct number of significant digits.
1 answer