Osmosis practical

Question 1

Independent variable

Answer 1

The concentration of salt particles

Question 2

Dependent variable

Answer 2

The mass of the potatoes

Question 3

Control variable

Answer 3

Volume of solution
solution
length of potato
same potato

Question 4

Risk and management

Answer 4

Cutting potato cylinders

use of electrical equipment

Question 5

Equipment

Answer 5

potato
cork borer/ potato chipper
10 cm cubed measuring cylinder
labels
five boiling tubes
a test tube rack
paper towels
a sharp knife
a white tile
a range of salt
solutions( 1.0 M- 0.25M)
Distilled water
a top-pan balance) accurate to at least 0.01g)

Question 6

Method:

Answer 6

1) use a cork borer to cut 5 potato cylinders of the same diameter.
2)Trim the cylinders so that they are all the same length( about 3 cm)
3) accurately measure and record mass of each potato cylinder
measure 10 cm cubed of the 1.0 M salt solution and put into the first boiling tube. Label boiling tube as 1.0M salt
Repeat step 4 to produce the additional labelled boiling tubes containing solutions of 0.75M, O.5M and 0.25M
Measure 10cm cubed of the distilled water and put into the fifth boiling tube. Label boiling tube as water.
Add one potato cylinder to each boiling tube. Make sure you know the mass of each potato cylinder in each boiling tube
Record the masses of each potato cylinder in a table.
Leave the potato cylinders from the boiling tubes for 30 min in the test tube rack
Remove the cylinders from the boiling tubes and carefully blot them dry with the paper towels
Re-measure the mass of cylinder( make sure know which one is which) Record your measurements the table. Then calculate the changes in the mass of each potato cylinder.
Plot a graph with change in mass in g on the y axis and concentration of sugar solution on the x axis

Question 7

Conclusion

Answer 7

The graph has a negative correlation. As the percentage of mass decreases the concentration of salt solution increases. Mass% decreases when left in a salt concentration. The potato is hyperton as the percentage mass going down meaning less solvent and a lot going out. Mass went up when placed in distilled water. But the last one became hypotonic because the particles moving in. Less particles outside potato then inside of cell so water moves out.