How many ions form when 39 grams of calcium fluoride are added to excess water? a. 0.50 mol b. 1.0 mol c. 1.5 mol d. 3.0 mol

Question

Ray Mckinney

Chemistry

29 February, 22:16

How many ions form when 39 grams of calcium fluoride are added to excess water? a. 0.50 mol b. 1.0 mol c. 1.5 mol d. 3.0 mol

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Answers (2)

Know the Answer?

Brynn Riddle · Answer 1

1.5 mol ions

Rubi Garrett · Answer 2

c. 1.5 mol

Explanation:

Firstly, we need to calculate the no, of moles of 39.0 grams of calcium fluoride.

n = mass / molar mass = (39.0 g) / (78.07 g/mol) = 0.499 mol ≅ 0.5 mol.

CaF₂ ionized in water as:

CaF₂ → Ca⁺² + 2F⁻.

Every 0.1 mole of CaF₂ is ionized to 3 ions (1 ion of Ca⁺² and 2 ions of F⁻).

So, 0.5 mol of CaF₂ will contain (3 x 0.5 mol = 1.5 mol) of ions.

Thus, the right choice is "c. 1.5 mol".