Answer:
4.998 × 10²⁴ amu
Explanation:
Given data:
Mass of substance = 8.3 g
Atomic mass unit = ?
Solution:
The mass of one mole of substance is equal the gram per mole of that substance.
atomic mass unit = g/mol
For 8.3 g:
8.3 × 6.022×10²³
4.998 × 10²⁴ amu
The number 6.022 × 10²³ is called Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
Answer:
An oxygen molecule consists of two oxygen (o2) atoms bound together and a water molecule consists of two hydrogen atoms and one oxygen atom (h20). H20 has a higher evaporation temperature than oxygen therefore it stays a liquid at room temperature unlike oxygen. Both have oxygen atoms.
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:
0.97014 moles KMnO4
Explanation:
1 g KMnO4 = 0.00633 mol
153.26 g x 0.00633 mol/ 1 g KMnO4 = 0.97014 moles KMnO4
