Solutions & Solubility

• Soluble: capable of being dissolved

• Solution: a homogeneous mixture of 2 or more substances in a single phase

• Solvent: the dissolving medium (something is being dissolved into it)

• Solute: the substance being dissolved

*the solute is generally the substance present in smaller quantity

Factors Affecting the Rate of Dissolution

1. Increasing the surface area of the solute (crushing into smaller pieces)

2. Agitating a solution

3. Heating a solvent

Solutions & Solubility

• Solubility: the amount of a substance that is required to form a saturated solution with a specific amount of solvent at a specified temperature– Saturated: a solution that contains the

maximum amount of dissolved solute– Unsaturated: contains less solute than the

saturated solution under the same conditions– Supersaturated: contains more solute than

the saturated solution

Solutions & Solubility

• A solution is in solution equilibrium when dissolving and recrystallization are occurring at the same rate.

• Overall, it appears that nothing is going on, because the competing processes are occurring at the same rate

• This equilibrium occurs at the saturation point

Solutions & Solubility

• How many grams of NaNO3 would dissolve in 100 g of water at 30˚C?

• How many grams of NaNO3 would dissolve in 245 g of water at 30˚C?

• How many grams of NH3 would be needed to make a saturated solution using 478 grams of water at 10˚C?

• How much water is needed to make a saturated KNO3 solution with 45 grams of KNO3 at 50˚C?

• 125 grams of water is used to make a saturated KNO3 solution at 20˚C. How many more grams of KNO3 could be dissolved if the temperature is raised to 50˚C?

Calculation of Molarity

How to make a molar solution1) Figure out how many grams of

solute are needed. 2) Add solute to volumetric flask of

the appropriate volume. 3) Fill to the line with solvent and

mix.**Notice that you are concerned with

the total volume of the solution NOT the volume of solvent used.

If you have 3.50 L of solution that contains 90.0 g of sodium chloride (NaCl) what is

the molarity of the solution?

If you have 3.50 L of solution that contains 90.0 g of sodium chloride (NaCl) what is

the molarity of the solution?

If you have 3.50 L of solution that contains 90.0 g of sodium chloride (NaCl) what is

the molarity of the solution?

If you have 3.50 L of solution that contains 90.0 g of sodium chloride (NaCl) what is

the molarity of the solution?

A solution was prepared by dissolving 17.1 g of sucrose (C12H22O11) in enough water to make 0.250 L of solution. What is the molarity of

this solution?

• Describe how you would make 200. mL of a 1.0 M NaCl solution.

A solution was prepared by dissolving 17.1 g of sucrose (C12H22O11) in 125 g of water. Find

the molal concentration of this solution.

A solution was prepared by dissolving 17.1 g of sucrose (C12H22O11) in 125 g of water. Find

the molal concentration of this solution.

A solution was prepared by dissolving 17.1 g of sucrose (C12H22O11) in 125 g of water. Find

the molal concentration of this solution.