Answer:c
Explanation:
I think because ca^+2
It’s loses the ion and if u look back u would see that a cation is a t charge but it’s not Goan that electron it’s losing that electron
The answer to this question is A- evaporation
Answer:Water contains Oxygen the purified the methane gas
Explanation:
For a closed system, you need two things:
1) a conservation of mass within the boundaries of the system
2) the ability to freely exchange energy to & from the "closed" system with a surrounding external system
So, the answer is <u><em>never</em></u>, since your defining the "system" as the water within the bathtub, and an open bathtub is exposed to evaporation, which is not conserving mass within the defined "system".