The best answer choice you could go for is B pure substance, a pure substance is a compound that is made of one element, like a diamond.
Answer:
Decreases
Explanation:
The atmospheric pressure on the surface of the mercury pushes it up the evacuated tube until the downward pressure of the mercury equals the atmospheric pressure.
If the atmospheric pressure decreases, the mercury doesn't have to rise as high.
The mercury height decreases.
Answer: i think it's 4 oxygen atoms
Explanation:
so sorry if i'm wrong