1. Solutions:MOLARITY
Monday, April 24th, 2017

2. Aqueous Solutions
In Chemistry, many reactions take place in water. This is also true for Biological processes.
Reactions that take place in water are said to occur in an aqueous solution.
Three types of reactions take place in aqueous solutions: Precipitation, Acid-Base and Redox.

3. Properties of Aqueous Solutions
Solution- a homogeneous mixture of two or more substances.
Solute- a substance in a solution that is present in the smallest amount.
Solvent- a substance in a solution that is present in the largest amount.
In an aqueous solution, the solute is a liquid or solid and the solvent is always water.

4. Solutions Solvent solute
When the solvent is water the solution is said to be aqueous

5. Molarity (M) Molarity (M) = moles of solute 1 liter solution
A concentration that expresses the moles of solute in 1 L of solution
Molarity (M) = moles of solute
1 liter solution
Other Common Rearrangements:

6. Units of Molarity 2.0 M HCl = 2.0 moles HCl 1 L HCl solution

7. Example Molarity Calculation
NaOH is used to open stopped sinks, to treat cellulose in the making of nylon, and to remove potato peels commercially.
If 4.0 g NaOH are used to make 500. mL of NaOH solution, what is the molarity (M) of the solution?

8. 4.0 g NaOH x 1 mole NaOH = 0.10 mole NaOH
500. mL x L = L
1000 mL
0.10 mole NaOH = mole NaOH
0.500 L L
= 0.20 M NaOH

9. Molarity Conversion Factors
A solution is a 3.0 M NaOH. Write the molarity in the form of conversion factors.
3.0 moles NaOH and L NaOH soln
1 L NaOH soln moles NaOH