Molar Concentration

C6

Molarity

Molarity is the measure of the concentration of a solution.

Molarity (M) = moles of solute (n) Liters of solution (V)

Units of Molarity are mol / L or M

Calculating molarity, find M 1.  What is the molarity of a solution that contains

2.0 moles of sugar dissolved in 1.5L of solution?

Calculating molarity, find M 2. What is the molarity of a solution that contains .5 moles of salt dissolved in 3.0 L of

solution?

Calculating the number of moles of solute, then find the molarity. (find n, then M)

3.  60g of NaOH is placed in 1.0L of solution, what is the molarity of the solution?

Calculating the number of moles of solute, then find the molarity. (find n, then M)

4.  117 g of NaCl is placed in 2.5L of solution, what is the molarity of the solution?

Calculate the number of moles. Find n

5. How many moles of KNO3 would be needed to make 1.5L of a .75M solution?

In the laboratory

6. A chemist wants to make .5L of a 20M solution using NaOH. The solution will be made from solid NaOH and water. How many grams of

NaOH are needed to make this solution?

Molarity Lab

Group 1 : .1M NaCl

.1L

Group 2: .15M NaCl

.1L

Group 3: .20M NaCl

.1L

Group 4: .25M NaCl

.1L

Group 5 : .3M NaCl

.1L

Group 6: .35M NaCl

.1L

Group 7: .4M NaCl

.1L

Group 8: .45M NaCl

.1L

Calculating the volume needed to create a solution of a specified molarity. Find V

7. Determine how many liters of a 1.5M solution are needed to obtain 2.5 moles of NaCl.

Calculating the volume needed to create a solution of a specified molarity. Find V

8. Determine how many liters of a .75M solution are needed to obtain 1.25 moles of NaOH.

Calculate the amount of a concentrated solution needed to make a more dilute solution. Find V

9. How many milliliters of 5.0M solution do you need to obtain .5L of 2.5M solution?

Distilled Water 5.0M solution

.5L 2.5M

Calculate the amount of a concentrated solution needed to make a more dilute solution. Find V

9. How many milliliters of 5.0M solution do you need to obtain .75 L of 1.25M solution?

Distilled Water 5.0M solution

.75L 1.25M

Molarity Lab

Group 1 : .4M HCl

.1L

Group 2: .35M HCl

.1L

Group 3: .3M HCl

.1L

Group 4: .25M HCl

.1L

Group 5 : .2M HCl

.1L

Group 6: .15M HCl

.1L

Group 7: .1M HCl

.1L

Group 8: .125M HCl

.1L