To find out how many grams of ammonia (NH3) are needed for 3.4 moles, we can use the molar mass of ammonia. The molar mass is calculated by adding the atomic masses of nitrogen (N) and hydrogen (H).
1. The atomic mass of nitrogen (N) is approximately 14.01 g/mol, and each hydrogen (H) atom has an atomic mass of about 1.01 g/mol. Since there are three hydrogen atoms in NH3, we need to calculate:
- Molar mass of NH3 = 14.01 g/mol (N) + 3 × 1.01 g/mol (H) = 14.01 g/mol + 3.03 g/mol = 17.04 g/mol.
2. Now that we have the molar mass of NH3, we can find the mass required for 3.4 moles using the formula:
Mass (grams) = Moles × Molar Mass (g/mol)
3. Plugging in the values:
Mass = 3.4 moles × 17.04 g/mol = 57.9996 grams.
4. Rounding this to three significant figures, we find that you need approximately 58.0 grams of ammonia (NH3) to weigh out 3.4 moles.