Mole Calculations and Answers - Mole Calculation Worksheet 1 How ... - Free Printable

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However, based on the visible portion of your message, here are the likely questions (as commonly found in such worksheets):

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Mole Calculation Worksheet

1. How many moles are in 10 grams of NaCl?
2. How many grams are in 3.5 moles of Au?
3. How many moles are in 10 grams of MgO?
4. How many moles are in 2.5 moles of magnesium?
5. How many moles are in 1.2 grams of potassium?
6. How many moles are in 0.8 grams of lithium?
7. How many grams are in 0.8 moles of sodium?
8. What is the molecular weight of the following compounds?
a) NaCl
b) CaCl₂
c) H₂O
d) C₆H₁₂O₆

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Let me solve each one step by step.

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Solution:

#### 1. How many moles are in 10 grams of NaCl?

- Molar mass of NaCl = 23 (Na) + 35.5 (Cl) = 58.5 g/mol
- Moles = mass / molar mass = 10 g / 58.5 g/mol ≈ 0.171 moles

✔ Answer: 0.171 mol

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#### 2. How many grams are in 3.5 moles of Au (Gold)?

- Molar mass of Au = 197 g/mol
- Mass = moles × molar mass = 3.5 mol × 197 g/mol = 689.5 grams

✔ Answer: 689.5 g

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#### 3. How many moles are in 10 grams of MgO?

- Molar mass of MgO = 24 (Mg) + 16 (O) = 40 g/mol
- Moles = 10 g / 40 g/mol = 0.25 moles

✔ Answer: 0.25 mol

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#### 4. How many moles are in 2.5 moles of magnesium?

This question seems redundant — it says "how many moles are in 2.5 moles"? That’s just 2.5 moles.

But if it meant: “How many atoms are in 2.5 moles of magnesium?” then:

- Atoms = moles × Avogadro’s number = 2.5 × 6.022 × 10²³ = 1.5055 × 10²⁴ atoms

But as written, it’s likely a typo or misphrasing.

✔ Answer: 2.5 moles (if asking for moles)

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#### 5. How many moles are in 1.2 grams of potassium (K)?

- Molar mass of K = 39.1 g/mol
- Moles = 1.2 g / 39.1 g/mol ≈ 0.0307 moles

✔ Answer: 0.0307 mol

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#### 6. How many moles are in 0.8 grams of lithium (Li)?

- Molar mass of Li = 6.94 g/mol
- Moles = 0.8 / 6.94 ≈ 0.115 moles

✔ Answer: 0.115 mol

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#### 7. How many grams are in 0.8 moles of sodium (Na)?

- Molar mass of Na = 23 g/mol
- Mass = 0.8 mol × 23 g/mol = 18.4 grams

✔ Answer: 18.4 g

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#### 8. What is the molecular weight of the following compounds?

a) NaCl
= 23 + 35.5 = 58.5 g/mol

b) CaCl₂
= 40 (Ca) + 2×35.5 (Cl) = 40 + 71 = 111 g/mol

c) H₂O
= 2×1 + 16 = 18 g/mol

d) C₆H₁₂O₆ (glucose)
= 6×12 + 12×1 + 6×16 = 72 + 12 + 96 = 180 g/mol

✔ Answers:
- a) 58.5 g/mol
- b) 111 g/mol
- c) 18 g/mol
- d) 180 g/mol

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✔ Summary of Answers:

| Question | Answer |
|--------|--------|
| 1 | 0.171 mol |
| 2 | 689.5 g |
| 3 | 0.25 mol |
| 4 | 2.5 mol (or 1.5055 × 10²⁴ atoms if asking for particles) |
| 5 | 0.0307 mol |
| 6 | 0.115 mol |
| 7 | 18.4 g |
| 8a | 58.5 g/mol |
| 8b | 111 g/mol |
| 8c | 18 g/mol |
| 8d | 180 g/mol |

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