Answer:
20.53 g.
Explanation:
- Knowing that every 15.0 g of pure calcium fluoride contains 7.70 g of calcium.
Using cross multiplication:
15.0 g of pure calcium fluoride contains → 7.70 g of calcium.
40.0 g of pure calcium fluoride contains → ??? g of calcium.
∴ The mass of Ca in 40.0 g of calcium fluoride = (7.70 g)(40.0 g)/(15.0 g) = 20.53 g.
