OSMOSIS LAB
Osmosis: the movement of water molecules from
a region of lower solute concentration to a region
of higher solute concentration.
SOLUTION CONCENTRATIONS:

Isotonic: two solutions have the same
concentration of solutes. (iso- same, toncondition, -ic pertaining to)
Two solutions of different concentration:
 The one with more solute is hypertonic to the
solution with less solute. (hyper- more than)
 The solution that has less solute is hypotonic to
the one with more solute. (hypo- less than)
Semi-permeable membrane
IN WHAT DIRECTION WILL NET H2O
MOVEMENT OCCUR?
SET UP:

Six dialysis tubing bags are filled with (15-25mL)
six solutions of differing sucrose concentrations
and placed in beakers of distilled water.






0M
0.2M
0.4M
0.6M
0.8M
1.0M
Sucrose solution
Distilled water
Reminder:
Molarity (M) = mol/L
ex. 1 mole of sucrose per liter of water = 1.0M

RQ: HOW DOES THE MOLARITY OF A
SOLUTION EFFECT THE RATE OF OSMOSIS
THROUGH A SEMI PERMEABLE MEMBRANE?
Independent Variable:
 Dependent Variable:

PREDICTIONS?
Change
Initial Final
Contents in Dialysis Bag
in Mass
Mass (g) Mass (g)
(g)
a) 0M (distilled water)
26.0
b) 0.2M sucrose
26.2
c) 0.4M sucrose
26.1
d) 0.6M sucrose
26.4
e) 0.8M sucrose
26.3
f) 1.0M sucrose
26.4
RESULTS:
Contents in Dialysis Bag
Initial Final Mass Change in
Mass (g)
(g)
Mass (g)
a) 0M (distilled water)
26.0
26.3
0.3
b) 0.2M sucrose
26.2
27.0
0.8
c) 0.4M sucrose
26.1
28.1
2.0
d) 0.6M sucrose
26.4
29.3
2.9
e) 0.8M sucrose
26.3
30.2
3.9
f) 1.0M sucrose
26.4
31.2
4.8
Explain the relationship between the change in mass and
the molarity of sucrose within the dialysis tubing bag.
RELATIONSHIP?
Change in Mass vs. Molarity
6.0
Change in mass (g)
5.0
4.0
3.0
2.0
1.0
0.0
0
0.2
0.4
0.6
0.8
1
1.2
Molarity (M)
Predict what would happen to the mass of each bag in this
experiment if all the bags were placed in a 0.4M solution instead
of distilled water.