CHEMISTRY homework... need help?

Question

Suppose it is now year 2020 and you are one of the migrants to planet Chismoz whose atmosphere is almost similar to ours. You found numerous sources of water there but you are not sure which one is pure. Five samples were taken and with proper apparatus/ devices, they were chemically analyzed as follows:

SAMPLE %HYDROGEN %OXYGEN

A 15.51% 86.11%

B 20.00% 81.33%

C 11.11% 88.89%

D 11.92% 89.35%

E 25% 75%

a) which sample do you think is good for general consumption? Why?

b) what will you do with other samples in order to obtain additional sources of drinking water?

Answer 1

Been a while but I'm pretty sure you need to find the % composition of hydrogen and oxygen in H20. That should match one of the answers (or at least be close). In order to get more sources of drinking water you would have to evenly balance the others in the same way.

Answer 2

a. You have to know the percent composition of water. So you add the total molecular weight of water and then take that total and compare to the individual (that would be two hydrogens for one and the one oxygen for the other.

so:   H = 1.008 and O = 16.00 there for H + H + O = 18.016

H% = (2.016/18.016) X 100 = 11.11

the answer is C

b. Since the other samples are not pure the bust method is distillation or just boiling.