Moles To Mass Conversion | institutodecegosdabahia.org.br - Free Printable

Let's solve this Molar Mass Conversion Worksheet step by step.

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Part I: Molar Mass of Each Molecule/Compound

We will calculate the molar mass using atomic masses from the periodic table (rounded to nearest hundredth):

- H = 1.01 g/mol
- O = 16.00 g/mol
- N = 14.01 g/mol
- C = 12.01 g/mol
- Mg = 24.31 g/mol
- Cl = 35.45 g/mol
- Ag = 107.87 g/mol
- Pb = 207.2 g/mol
- I = 126.90 g/mol
- Al = 26.98 g/mol

Now, compute each:

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1. H₂
= 2 × 1.01 = 2.02 g/mol

2. O₂
= 2 × 16.00 = 32.00 g/mol

3. H₂O
= (2 × 1.01) + 16.00 = 2.02 + 16.00 = 18.02 g/mol

4. H₂O₂
= (2 × 1.01) + (2 × 16.00) = 2.02 + 32.00 = 34.02 g/mol

5. MgCl₂
= 24.31 + (2 × 35.45) = 24.31 + 70.90 = 95.21 g/mol

6. CH₄
= 12.01 + (4 × 1.01) = 12.01 + 4.04 = 16.05 g/mol

7. (NH₄)₂O
- NH₄⁺ = 14.01 + (4 × 1.01) = 14.01 + 4.04 = 18.05
- Two NH₄⁺ = 2 × 18.05 = 36.10
- Add O = 16.00 → Total = 36.10 + 16.00 = 52.10 g/mol

8. AgNO₃
- Ag = 107.87
- N = 14.01
- O₃ = 3 × 16.00 = 48.00
- Total = 107.87 + 14.01 + 48.00 = 169.88 g/mol

9. PbI₂
- Pb = 207.2
- I₂ = 2 × 126.90 = 253.80
- Total = 207.2 + 253.80 = 461.00 g/mol

10. Al(CN)₃
- Al = 26.98
- CN = 12.01 + 14.01 = 26.02
- Three CN groups = 3 × 26.02 = 78.06
- Total = 26.98 + 78.06 = 105.04 g/mol

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✔ Part I Answers:

1. H₂: 2.02 g/mol
2. O₂: 32.00 g/mol
3. H₂O: 18.02 g/mol
4. H₂O₂: 34.02 g/mol
5. MgCl₂: 95.21 g/mol
6. CH₄: 16.05 g/mol
7. (NH₄)₂O: 52.10 g/mol
8. AgNO₃: 169.88 g/mol
9. PbI₂: 461.00 g/mol
10. Al(CN)₃: 105.04 g/mol

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Part II: Dimensional Analysis

Use the formula:
$$
\text{moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}
\quad \text{or} \quad
\text{mass (g)} = \text{moles} \times \text{molar mass (g/mol)}
$$

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#### 1. How many moles are present in 9.06 g of hydrogen gas (H₂)?

- Molar mass of H₂ = 2.02 g/mol
- Moles = $ \frac{9.06}{2.02} = 4.485 \approx \boxed{4.49} $ mol

✔ Answer: 4.49 mol

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#### 2. How many grams are present in 0.82 moles of oxygen gas (O₂)?

- Molar mass of O₂ = 32.00 g/mol
- Mass = 0.82 mol × 32.00 g/mol = 26.24 g

✔ Answer: 26.24 g

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#### 3. How many grams exist in 2.78 mol of water (H₂O)?

- Molar mass of H₂O = 18.02 g/mol
- Mass = 2.78 × 18.02 = 49.9956 ≈ 50.00 g

✔ Answer: 50.00 g

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#### 4. How many grams exist in 0.49 mol of hydrogen peroxide (H₂O₂)?

- Molar mass of H₂O₂ = 34.02 g/mol
- Mass = 0.49 × 34.02 = 16.6698 ≈ 16.67 g

✔ Answer: 16.67 g

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✔ Final Answers for Part II:

1. 4.49 mol
2. 26.24 g
3. 50.00 g
4. 16.67 g

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