Post Lab Assignment for Osmosis La
Assume that you have a 20 M glycerol stock solution. You need to make 5 different solutions for your experiment: 0 M or no glycerol, 2.5 M glycerol, 5 M glycerol, 7.5 M glycerol and 10 M glycerol. In each experiment you will need to make 50 ml of the diluted solution.
Final Conc. Solution (C2)
Amount (V1) of 20 M Glycerol Stock Solution (C1) Needed
Amount of Water (V2-V1)
Final Volume of the Solution (V2)
0 M Glycerol
0
0
50
2.5 Glycerol
6.25
43.75
50
5 M Glycerol
12.5
37.5
50
7.5 M Glycerol
18.75
31.25
50
10 M Glycerol
25
25
50
Report Format for at home experiment
· Name: Henry. Tolbert
· Date: 01/03/2021
· Picture of set up, including container, salt type used, and potato cubes aligned to show they are identical in size (with ruler visible)
· Time experiment started:
· Time experiment ended:
· Total time of incubation of potato cubes in various solutions:
· Picture of potato cubes at end of experiment in order of concentration of solution: 0M, 0.16M, 0.31M, 0.47M, 0.63M (with ruler visible)
· Description of size and texture changes for each cube:
Changes in size of cube
Changes in texture of cube
0M
2cm
Rough and extremely hard
0.16M
1.9cm
Rough, very hard
0.31M
1.7cm
Smooth, slightly soft
0.47M
1.3cm
Smooth, very soft
0.63M
1.2cm
Smooth, extremely soft
Determining the isotonic point of potato in NaCl
1. TABLE 2: Cumulative percent change in mass per time point for each potato plug.
Cumulative percent change in Mass of potato at various times
NaCl Concentration (M)
0
10 min
20 min
30 min
40 min
50 min
60 min
0
0
3.77
4.34
5.66
6.98
8.87
8.11
0.063
0
2.42
3.35
3.35
6.15
8.01
8.01
0.13
0
1.14
1.14
1.14
2.47
3.04
3.80
0.25
0
0
-1.28
-1.28
-2.56
-1.83
-1.83
0.63
0
-2.35
-5.42
-7.23
-8.32
-10.13
12.66
2. GRAPH 1: cumulative percent change vs. time for each potato plug.
Use Excel to get the slope (rate) of each line.
3. TABLE 3: RATE of cumulative percent change (slope of each line).
NaCl Concentration (M)
Rate of change
0
-1.29
0.063
-1.646
0.13
-0.701
0.25
0.615
0.63
-3.261
4. GRAPH 2: RATE of cumulative percent change vs. solution molarity for each sample. Use Excel to get the equation of the line.
5. Isotonic point of potato in NaCl and discuss how this aligns or doesn’t fit with your home experiment results. Use the formula for a line with Y=0 and solve for X.
-3.261
Post Lab Assignment for Osmosis La
Assume that you have a 20 M glycerol stock solution. You need to make 5 different solutions for your experiment: 0 M or no glycerol, 2.5 M glycerol, 5 M glycerol, 7.5 M glycerol and 10 M glycerol. In each experiment you will need to make 50 ml of the diluted solution.
Final Conc. Solution (C2)
Amount (V1) of 20 M Glycerol Stock Solution (C1) Needed
Amount of Water (V2-V1)
Final Volume of the Solution (V2)
0 M Glycerol
0
0
50
2.5 Glycerol
6.25
43.75
50
5 M Glycerol
12.5
37.5
50
7.5 M Glycerol
18.75
31.25
50
10 M Glycerol
25
25
50
Report Format for at home experiment
· Name: Henry. Tolbert
· Date: 01/03/2021
· Picture of set up, including container, salt type used, and potato cubes aligned to show they are identical in size (with ruler visible)
· Time experiment started:
· Time experiment ended:
· Total time of incubation of potato cubes in various solutions:
· Picture of potato cubes at end of experiment in order of concentration of solution: 0M, 0.16M, 0.31M, 0.47M, 0.63M (with ruler visible)
· Description of size and texture changes for each cube:
Changes in size of cube
Changes in texture of cube
0M
2cm
Rough and extremely hard
0.16M
1.9cm
Rough, very hard
0.31M
1.7cm
Smooth, slightly soft
0.47M
1.3cm
Smooth, very soft
0.63M
1.2cm
Smooth, extremely soft
Determining the isotonic point of potato in NaCl
1. TABLE 2: Cumulative percent change in mass per time point for each potato plug.
Cumulative percent change in Mass of potato at various times
NaCl Concentration (M)
0
10 min
20 min
30 min
40 min
50 min
60 min
0
0
3.77
4.34
5.66
6.98
8.87
8.11
0.063
0
2.42
3.35
3.35
6.15
8.01
8.01
0.13
0
1.14
1.14
1.14
2.47
3.04
3.80
0.25
0
0
-1.28
-1.28
-2.56
-1.83
-1.83
0.63
0
-2.35
-5.42
-7.23
-8.32
-10.13
12.66
2. GRAPH 1: cumulative percent change vs. time for each potato plug.
Use Excel to get the slope (rate) of each line.
3. TABLE 3: RATE of cumulative percent change (slope of each line).
NaCl Concentration (M)
Rate of change
0
-1.29
0.063
-1.646
0.13
-0.701
0.25
0.615
0.63
-3.261
4. GRAPH 2: RATE of cumulative percent change vs. solution molarity for each sample. Use Excel to get the equation of the line.
5. Isotonic point of potato in NaCl and discuss how this aligns or doesn’t fit with your home experiment results. Use the formula for a line with Y=0 and solve for X.
-3.261
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