1. Bellwork Friday
Draw and finish filling in the mole road map to the right.

2. Dilute solution- Contains a small amount of solute
16. 2
Concentration -a measure of the amount of solute per given amount of solvent or solution.
Measured in units of molarity
Dilute solution- Contains a small amount of solute
Concentrated solution- Contains a large amount of solute

3. Molarity(M) = moles of solute
liters of solution
A 1 M solution contains 1 mole of solute per 1 L of solution. A 0.5 M NaCl solution has 0.5 mol NaCl in 1 L total solution.

4. EXAMPLES:
What is the concentration in molarity of a solution made with 1.25 mol NaOH in 4.0 L of solution?
# mol
# L
M =
M = ?
#mol = 1.25 mol
V = 4.0 L
M = 1.25 mol
4.0 L
= M
= M

5. Question
A student measures 58.5g of NaCl and dissolves in into a 1.0 L of water. What is the molarity of the solution?

6. Dilutions
Diluting a solution won’t change the number of moles of solute. It only changes the concentration.
M1V1 = M2V2
This formula works only for dilution of a solution!!!!
Don’t use it for a reaction!

7. How would you make 500. mL of 6.0 M NaOH from 12.0M NaOH?
To make the solution, you would measure out 250. ml of the concentrated base and add it to water until you have 500. ml of solution.
M1 = 12.0M V1 = ?
M2 = 6.0M V2 = 500. mL
(12.0M)(x) = (6.0M)(500. ml)
X = 250. ml
How many grams of NaOH would be necessary to make 250.ml of 12.0 M solution?
250. ml NaOH 1L NaOH 12.0 mol NaOH 40.0 g NaOH =
1000 ml 1 L NaOH 1 mol NaOH
120. g NaOH

8. Question
A solution is made with 10.5g AgCl dissolved in 2.0L of water. What is the molarity of the silver chloride solution?

9. EXAMPLE:
For a lab we need 500. mL of 4.25 M HCl. Concentrated HCl is 12.0 M. How do we make up the solution?
M1V1 = M2V2
M2 = M
V2 = mL
M1 = M
V1 = ?
(12.0 M)(V1) = (4.25M)(500. mL)
V1 = 177 mL
Add 177 ml of concentrated hydrochloric acid to enough water to make 500 ml of solution.

10. Solution Stoichiometry
use Molarity as a conversion factor#
# mol
1 L
1 L
# mol

11. EXAMPLES:
What volume of M nitric acid is required to react completely with L of M Ba(OH)2?
2HNO3 + Ba(OH)2 → Ba(NO3) H2O
0.386 L Ba(OH)2
mol Ba(OH)2
2 mol HNO3
1 L HNO3
1 L Ba(OH)2
1 mol Ba(OH)2
0.246 mol HNO3
molarity
mol-mol ratio
molarity =
0.162 L HNO3

12. Calculate the number of grams of carbon dioxide that can react with 0
Calculate the number of grams of carbon dioxide that can react with L of a M solution of potassium hydroxide, according to the following reaction:
2KOH CO2  K2CO H2O
0.135 L KOH
0.357 mol KOH
1 mol CO2
44.0 g CO2
1 L KOH
2 mol KOH
1 mol CO2
= 1.06 g CO2
molarity
mol-mol ratio
GFM

13. % Solutions Percent by volume % v/v = volume solute (mL) x 100
volume solution (mL)
Percent mass/volume
% m/v = mass solute(g) x 100

14. EXAMPLES:
Rubbing alcohol is 70.0% isopropyl alcohol by volume. How many mL of isopropyl alcohol are in a 250 mL bottle of this solution?
% v/v = volume solute (mL) x 100
volume solution (mL)
% v/v = 70.0 %
v solution = 250 mL
v solute = X
70.0 % = __X__ x 100
250 mL
X = 175 mL

15. If the % mass/volume (m/v) for a solute is 6
If the % mass/volume (m/v) for a solute is 6.80 %, and the volume of the solution is 42.6 mL, what mass of the salt is present?
% m/v = mass solute (g) x 100
volume solution (mL)
% m/v = 6.80 %
v solution = 42.6 mL
g solute = X
6.80 % = __X__ x 100
42.6 mL
X = g
= g

16. Warm-up Tuesday
Calculate the number of grams of carbon dioxide that can react with L of a M solution of potassium hydroxide, according to the following reaction:
2KOH CO2  K2CO H2O