Chemistry worksheet focusing on mole problems, including molar mass calculations and mole conversions.

- HCl: 1.008 g/mol (H) + 35.45 g/mol (Cl) = 36.458 g/mol
- K₂CO₃: 2×39.10 g/mol (K) + 12.01 g/mol (C) + 3×16.00 g/mol (O) = 78.20 + 12.01 + 48.00 = 138.21 g/mol
- Ca(OH)₂: 40.08 g/mol (Ca) + 2×(16.00 g/mol (O) + 1.008 g/mol (H)) = 40.08 + 2×17.008 = 40.08 + 34.016 = 74.096 g/mol
- Na₃PO₄: 3×22.99 g/mol (Na) + 30.97 g/mol (P) + 4×16.00 g/mol (O) = 68.97 + 30.97 + 64.00 = 163.94 g/mol

1. Atoms in 6.2 moles of aluminum:
- Use Avogadro's number: 6.022 × 10²³ atoms/mol
- Calculation: 6.2 mol × 6.022 × 10²³ atoms/mol = 3.73364 × 10²⁴ atoms
- Answer: 3.7 × 10²⁴ atoms (rounded to two significant figures)

2. Convert 5.3 × 10²⁵ molecules of CO₂ to moles:
- Use Avogadro's number: 6.022 × 10²³ molecules/mol
- Calculation: (5.3 × 10²⁵ molecules) / (6.022 × 10²³ molecules/mol) = 87.99... mol
- Answer: 88 mol (rounded to two significant figures)

3. Formula units in 0.87 moles of sodium acetate:
- Use Avogadro's number: 6.022 × 10²³ formula units/mol
- Calculation: 0.87 mol × 6.022 × 10²³ formula units/mol = 5.23914 × 10²³ formula units
- Answer: 5.2 × 10²³ formula units (rounded to two significant figures)

4. Convert 3.55 moles NaCl to formula units:
- Use Avogadro's number: 6.022 × 10²³ formula units/mol
- Calculation: 3.55 mol × 6.022 × 10²³ formula units/mol = 2.13781 × 10²⁴ formula units
- Answer: 2.14 × 10²⁴ formula units (rounded to three significant figures)