Answer:
The water in the leaf will evaporate
Explanation:
the leaf would absorb the water and when sat in the sun, the water would evaporate and the leaf would dry out
Answer:
Phenolphthalein is an indicator. It is pink in alkaline solutions and turns colourless as the pH decreases.
It can be used to measure the activity of the enzyme lipase on the breakdown of lipids.
Samples of milk containing phenolphthalein were incubated with lipase at different temperatures.
The time taken for the phenolphthalein to turn colourless was recorded and used to calculate the rate of enzyme activity.
Figure 10 shows these results.
Picture
(a) (i) Explain why phenolphthalein turns colourless when lipase breaks down the lipids in milk. (2)
(ii) Describe the effect of temperature on the activity of lipase, as shown in Figure 10. (2)
(iii) Explain why the activity of lipase changes above a temperature of 40°C. (2)
(b) A student investigated the time taken for amylase to breakdown a 10% starch solution into glucose at 37°C. The student repeated the investigation five times.
Answer:
The limiting reactant is salicylic acid.
Explanation:
From the equation of reaction,
1 mole of acetic anhydride (C4H6O3) (102g) reacts with 2 moles of salicylic acid (C7H6O3) (276 g)
80 g of acetic anhydride would react with (80×276/102) = 216.5 g of salicylic acid
216.5 grams of salicylic acid that is required to react with 80 grams of acetic anhydride.
The available mass of salicylic acid is 70 grams which makes salicylic acid the limiting reactant.
Answer: Although it is possible to have more than one state, it is also possible to have only one state.
Explanation: Just took the test