Lesson 2Ion

Concentration + Formulas

Ion concentrations in solutions

• Since salts will dissociate into ions when dissolved, we must learn how to calculate ion concentrations in a solution.– very similar to our Equilibrium calculations

from unit 2. – we still need mole ratios from the equation.

What is the concentration of each ion in 2.0 L of a 0.300 M AlCl3 solution?

0.300 M 0.300 M 0.900 M

AlCl3(s) Al3+ + 3Cl-

Try: What is the concentration of all ions present in a saturated solution of Ag2CO3 having a concentration of 1.2 x 10 -4 M?

What is the concentration of each ion in the solution formed by dissolving 80.0 g of CaCl2 in 600.0 mL of water?

1.20 M1.20 M

CaCl2 Ca2+ + 2Cl-

0.600 L

111.1 g

1 mole 80.0 g x

Molarity = moles L

= 1.20 M

2.40 M

Dilutions!If 5.0mL of 0.020 M Cl-1 is added to 15.0 mL of 0.012 M Br-1, what is the

molarity of the Cl-1 and Br-1 ions in the mixture?

Try…If 4.0mL of 0.1M I-1 is added to 16.0 mL of 0.02 M Cl-1, what is the molarity of the Cl-1 and I-1 ions in the mixture?

If 40.0 mL of 0.400 M AlCl3 solution is added to 60.0 mL of 0.600 M CaCl2

solution, what is the resulting concentration of all ions?

[Cl-] = 0.480 + 0.720 M = 1.200 M

AlCl3 Al3+ + 3Cl-

0.480 M0.160 M0.400 M40.0 x

100.0

CaCl2 Ca2+ + 2Cl-

0.600 M 60.0 x

100.0

0.360 M 0.720 M

Try…If 30.0 mL of 0.300 M AlBr3 solution is added to 70.0 mL of 0.700 M CaBr2

solution, what is the resulting concentration of all ions?

If the [Cl-] = 0.600 M, calculate the number of grams AlCl3 that would be

dissolved in 3.00 L of water.

AlCl3 Al3+ + 3Cl-

0.200 M 0.200 M 0.600 M

= 80.1 gx 133.5 g

1 mole

0.200 mole

1 L

3.00 L x

Try…If the [Cl-] = 0.200 M, calculate the number of grams MgCl2 that

would be dissolved in 2.00 L of water.

Writing formula equationcomplete ionic equation and

net ionic equations

Write the formula, complete, and net ionic equation for the reaction which occurs when 0.2 M solutions of Pb(NO3)2 (aq) and FeCl3(aq) are mixed.

Try: Write the formula, complete, and net ionic equation for the reaction which occurs when 0.2 M solutions of magnesium sulphide

and strontium hydroxide are mixed.

Homework

Hebden: pg. 78 #12, 13,14 pg. 81 #18, 19, and 20 (a, c, f, h)