Solutions #3

Chemistry 2202

Name:

Dissociation and Ion Concentration 1.

Write an equation to show what happens when each of the following dissolves in water.

a) Li3 PO4(s) → 3 Li+(aq) + PO43-(aq) b) MgF2(s) → Mg2+(aq) + 2 F-(aq) c) HNO3(aq) → H+(aq) + NO3-(aq) d) CH3OH(l) → CH3OH(aq) e) (NH4)3PO4(s) → 3 NH4+(aq) + PO43-(aq) f) C6 H12O11 (s) → C6 H12O11 (aq) g) Sr(OH)2(s) → Sr2+(aq) + 2 OH-(aq)

2.

Determine the concentration of aqueous sulfate ion in a 0.25 mol/L solution of Al2(SO4)3(aq). Al2(SO4)3(aq) → 2 Al3+(aq) + 3 SO42-(aq) 0.25 mol/L

3.

0.50 mol/L

0.75 mol/L

What is the [OH-(aq)] in 0.45 M strontium hydroxide? Sr(OH)2(s) → Sr2+(aq) + 2 OH-(aq) 0.45 M

4.

→ 0.45 M

0.90 M

Determine the concentration of aqueous magnesium and aqueous acetate ions in a 0.75 M solution of magnesium acetate.

Mg(CH3COO)2(aq) → Mg2+(aq) + 2 CH3COO-(aq) 0.75 mol/L

0.75 mol/L

1.50 mol/L

Solutions #3

5.

Chemistry 2202

Name:

The concentration of aqueous nitrate ion in a solution of Al(NO3)3 is determined to be 0.50 mol/L. What is the concentration of the aluminum nitrate solution?

Al(NO3)3(aq) → Al3+(aq) + 3 NO3-(aq) 0.17 mol/L 6.

0.50 mol/L

What is the concentration of aqueous ammonium ion in a solution prepared by dissolving 2.50 g of (NH4)3PO4(s) in enough water to make 0.250 L of solution?

(NH4)3PO4(s) → 3 NH4+(aq) + PO43-(aq) 2.50 g 0.01677 mol 0.0671 mol/L

7.

0.201 mol/L

What mass of (NH4)2CO3(s) must be dissolved in enough water to make a 500.0 mL solution in which the [NH4+(aq)] is 0.19 mol/L?

(NH4)2CO3(s) → 2 NH4+(aq) + CO32-(aq) 0.095 mol/L 0.0475 mol 4.57 g

← 0.19 mol/L