Question

complete the tables by determining the moles and numbers of ions of each type present in the following aqueous solutions.

note: reference the fundamental constants table for additional information.

part 1 of 2

\\(718.\text{ ml}\\) of \\(0.618\text{ m}\\) aluminum chloride. be sure your answer has the correct number of significant figures.

part 2 of 2

\\(79.0\text{ ml}\\) of \\(1.35\text{ m}\\) magnesium chloride. be sure your answer has the correct number of significant figures.

Explanation:

Calculate moles of solute for Part 1

Using the Molarity and Molarity Calculations knowledge points

$$ \text{Moles of } \text{AlCl}_3 = 0.718\text{ L} \times 0.618\text{ M} = 0.443724\text{ mol} $$

$$ \text{Moles of } \text{Al}^{3+} = 0.443724\text{ mol} \approx 0.444\text{ mol} $$

$$ \text{Moles of } \text{Cl}^- = 3 \times 0.443724\text{ mol} = 1.331172\text{ mol} \approx 1.33\text{ mol} $$

Calculate number of ions for Part 1

Using the Molarity Calculations knowledge point

$$ \text{Ions of } \text{Al}^{3+} = 0.443724\text{ mol} \times 6.022 \times 10^{23}\text{ /mol} \approx 2.67 \times 10^{23} $$

$$ \text{Ions of } \text{Cl}^- = 1.331172\text{ mol} \times 6.022 \times 10^{23}\text{ /mol} \approx 8.02 \times 10^{23} $$

Calculate moles of solute for Part 2

Using the Molarity and Molarity Calculations knowledge points

$$ \text{Moles of } \text{MgCl}_2 = 0.0790\text{ L} \times 1.35\text{ M} = 0.10665\text{ mol} $$

$$ \text{Moles of } \text{Mg}^{2+} = 0.10665\text{ mol} \approx 0.107\text{ mol} $$

$$ \text{Moles of } \text{Cl}^- = 2 \times 0.10665\text{ mol} = 0.2133\text{ mol} \approx 0.213\text{ mol} $$

Calculate number of ions for Part 2

Using the Molarity Calculations knowledge point

$$ \text{Ions of } \text{Mg}^{2+} = 0.10665\text{ mol} \times 6.022 \times 10^{23}\text{ /mol} \approx 6.42 \times 10^{22} $$

$$ \text{Ions of } \text{Cl}^- = 0.2133\text{ mol} \times 6.022 \times 10^{23}\text{ /mol} \approx 1.28 \times 10^{23} $$

Answer:

Question 1

	Aluminum	Chloride
ions	\(2.67 \times 10^{23}\)	\(8.02 \times 10^{23}\)

Question 2

	Magnesium	Chloride
ions	\(6.42 \times 10^{22}\)	\(1.28 \times 10^{23}\)