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.
Molecules move the fastest in gas
Answer:
a). Nepthalene is a D2h molecule because it has 3 C2 axes which are perpendicular and it has a mirror plane which is horizontal. Moreover C2 is taken as principal axis.
b). 1,8-dichloronaphthalene is a C2v molecule beccause it has 1 C2 axis, two rings are joined by the C-C bond and it also has two mirro planes.
c). 1,5-dichloronaphthalene is a C2h molecule because it has only 1 C2 axis which is pependicular to the plane, it has an inversion center and also a mirror plane which is horizontal in position.
d). 1,2-dichloronaphthalene is a Cs molecule because it has only a mirror plane.
Answer:
Dioxide tetrachloride
Explanation:
Di meaning 2 as in o2 and tetra the Greek numerical for 4 attached to chlorine in a group it is Chloride.
