Practicals + Graphs + Apparatus Flashcards
What equipment is used to measure mass?
Top pan balance
When describing a graph, what word should be replaced in ‘the data flattened’
Flattened -> stayed constant
What does iodine test for?
-what is the colour change of a positive result?
Starch
-orange/brown -> blue/black
What does benedicts solution test for?
-what is the colour change of a positive result?
Sugar
-blue -> green/red
What does ethanol test for?
-what is the colour change of a positive result?
Lipids
-clear -> cloudy
What does biuret test for?
-what is the colour change of a positive result?
Protein
-blue -> purple
What is the magnification of an eyepiece lens?
10x
What apparatus measures rate of transpiration?
Bubble potometer
Describe the first half of a photosynthesis / light intensity graph, what is the limiting factor?
As light intensity increases, so does rate of photosynthesis. Light is the limiting factor
Describe the second half of a photosynthesis / light intensity graph, what is the limiting factor?
Increasing light will have no further effect on rate of photosynthesis. Carbon dioxide or temperature is the limiting factor
Describe the first half of a photosynthesis / carbon dioxide graph, what is the limiting factor?
As carbon dioxide concentration increases, so does rate of photosynthesis. Carbon dioxide is the limiting factor
Describe the second half of a photosynthesis / carbon dioxide graph, what is the limiting factor?
Increasing carbon dioxide concentration will have no further effect on rate of photosynthesis. Light intensity or temperature are the limiting factors
Describe the first third of a photosynthesis / temperature graph
As temperature increases, so does rate of photosynthesis
Describe and explain the optimum point on a photosynthesis / temperature graph
At the optimum temperature, rate of photosynthesis is highest because enzymes (involved in photosynthesis) are working at their greatest rate
Describe and explain the last third of a photosynthesis / temperature graph
Further increases in temperature causes enzymes to denature, decreasing the rate of photosynthesis
Describe the effect of light intensity on the rate of photosynthesis (2 marks)
As light intensity increases, so does rate of photosynthesis until it levels off and stays constant because if another limiting factor
Explain the effect of temperature on the rate of photosynthesis (3 marks)
As temperature increases, so does rate of photosynthesis because it reaches the optimum temperature for enzymes because of more collisions between enzymes and substrates. Beyond the optimum, rate decreases because enzymes denature
(Photosynthesis practical)
Why was sodium hydrogen carbonate used?
Encourages pondweeds to photosynthesise
(Photosynthesis practical)
What is the IV, DV and CV?
IV- light intensity
DV- oxygen produced
CV- plant used, temperature, carbon dioxide concentration
(Photosynthesis practical)
How is the IV changed?
Moving the lamp further away
(Photosynthesis practical)
Why is it better to use LED’s?
They wont affect temperature, ensuring more accurate results
(Photosynthesis practical)
How can accuracy be improved?
Collecting and measuring oxygen using a gas syringe
What 2 substances can be used to indicate the presence of carbon dioxide?
Lime-water and hydrogen carbonate
