Practice: A semipermeable membrane is placed between the following solutions.
Which solution will increase in volume?
Osmosis is the net movement of solvent across a semipermeable membrane.
Understanding Osmosis
Concept #1: Osmosis
Concept #2: Osmotic Pressure
Example #1: Osmosis is best defined as the movement of:
a) Water molecules across a semipermeable membrane into a region of low solute concentration.
b) Solute molecules from an area of high concentration to an area of lower concentration.
c) Solute molecules from an area of low concentration to an area of higher concentration.
d) Water molecules across a semipermeable membrane into a region of high solute concentration.
Practice: Four U tubes each have distilled water in the right arm, a solution in the left arm, and a semipermeable membrane between the arms. If the solute is LiF, which solution is most concentrated?
Practice: Identify the direction of water flow between 2 solutions separates by semipermeable membrane, where 
are the solute particles.
Concept #3: Tonicity of Solutions
Example #2: Label the tonicity of the solution outside the cell.
Practice: If the fluid surrounding a patient’s red blood cells is depleted in electrolytes, is crenation or hemolysis more likely to occur?
Practice: A solution with the same osmotic pressure as the blood is
Practice: A red blood cell placed in pure water will swell because:
