Required Practical Activity 3 - Investigate the effect of a range of concentrations of salt or sugar solutions on the mass of plant tissue Flashcards
What is the aim for investigating the effect of a range of concentrations of a range of salt or sugar solutions on the mass of plant tissue?
To investigate the effect of a range of concentrations of a range of salt or sugar solutions on the mass of plant tissue.
What is the apparatus needed for investigating the effect of a range of concentrations of a range of salt or sugar solutions on the mass of plant tissue?
- Potato
- Cork bearer
- Ruler
- Distilled water
- Sharp knife/scalpel
- White tile
- Paper towels
- Mass balance
- Five Petri dishes with labels
- Five different concentrations of sugar solution (0.00, 0.25, 0.50, 0.75 and 1.00M)
What is the method for investigating the effect of a range of concentrations of a range of salt or sugar solutions on the mass of plant tissue?
- Use a cork borer to cut five potato cylinders of the same diameter.
- Use the knife to trim off any potato skin on each potato cylinder. Then trim each potato cylinder so that they are all the same length.
- Accurately measure the mass of each potato cylinder.
- Accurately measure the length of each cylinder.
- Record your measurements in a table.
- Measure 10 cm3 of each concentration of sugar or salt solution and put into petri dishes. Label each boiling tube clearly.
- Measure 10 cm3 of the distilled water and put into the fifth boiling tube. Label the petri dishes clearly.
- Add one potato cylinder to each petri dish.
What is the conclusion for investigating the effect of a range of concentrations of a range of salt or sugar solutions on the mass of plant tissue?
In solution 0 mol/dm³ we saw an increase in the mass of the potato. This means that water moved into the potato. A solution of 0 mol/dm³ is pure water, we can say it is a dilute solution so water moved via osmosis from a dilute area outside the potato through the partially permeable membrane into the potato. This means that 0 mol/dm³ was a hypotonic solution.
In solution 0.5 mol/ dm³, there is now sugar dissolved in the water, this makes it more concentrated. We saw a decrease in the mass of the potato, this means that water moved out of the potato. Water moved via osmosis from a dilute are inside the potato to a more concentrated solution. This means that 0.5 mol/ dm³ was a hypertonic solution.
As the solutions became more concentrated, we saw increasingly more water leave the cell, this is because water moved from a more dilute area inside the potato chip to a more concentrated solution outside the potato chip via osmosis causing the potato chips to decrease in mass.
How do you calculated % change?
% change = (change in value / original value) x100
