Required Practical Flashcards
Explain why the apparatus must be air tight.
To prevent air entering or leaving as this would change the volume and therefore the pressure, effecting the movement of the coloured liquid.
Explain the purpose of the soda lime.
The oxygen produced is equal to the carbon dioxide released so the volume would remain constant.
Soda lime absorbs the carbon dioxide so the volume of oxygen absorbed can be measured.
Explain why the liquid would move in a certain direction.
The respiring organism takes in oxygen in the air in the experimental tube.
Carbon dioxide is used up by the soda lime.
Volume of gas decreases in the experimental tube, causing a decrease in pressure.
Lower pressure causes the liquid to move towards the experimental tube.
What are the units for rate of respiration?
Unit for volume.
per unit time.
per unit mass.
