Tuesday 16

1
Tuesday 1/6

• Whats a solution?
• What affects solution formation?
• What is concentration?
• How can it be measured?

2
Solutions

• A homogenous mixture
• The same composition throughout
• Cant tell the solute from the solvent
• Solute
• The substance that is being dissolved the
  smaller quantity
• Solvent
• The medium that a substance is dissolved in
• Water

3
Factors that affect Soln Formation

• The nature of the solute solvent
• Like dissolves like
• Polar molecules dissolve other polar things and
  nonpolar dissolves nonpolar
• Stirring (agitation)
• brings fresh solvent in contact with the solute
• Ex Kool Aid

4
More factors

• Temperature
• Higher temps mean more kinetic energy which
  dissolves solutes more quickly
• Ex Sugar in hot tea vs. ice tea
• Particle size
• Smaller particles expose more surface area of the
  solute to the solvent allowing it to dissolve
  more quickly
• Ex sugar cubes vs. granular sugar

5
Concentration

• A measure of how much solute is dissolved in a
  solvent.
• Dilute vs. Concentrated
• Dilute means there is a low amount of solute
• Low concentration
• Concentrated means there is a higher amount of
  solute
• High concentration
• Ex Kool aid w/ ½ cup of sugar vs. 1 cup

6
Molarity

• A way of expressing concentration numerically
• Abbreviated M
• M mol of solute
• L of solution
• M mol
• L

7
Example 1

• A saline solution contains 0.90 g of NaCl per 100
  mL of solution. What is the molarity of the
  solution?

8
Example 2

• How many moles of solute are present in 1.5 L of
  a 0.24 M Na2SO4 solution?

9
Example 3

• What is the molarity of a 4.00 L solution made
  with 400.0 g of CuSO4?

10
Example 4

• A 1500. mL solution is made with 0.060 mol of
  NaHCO3. What is its molarity?