The number of oxygen atoms = 3
Mass = 24 g
<h3>Further explanation</h3>
The formula of a compound shows the composition of the constituent elements
CaCO₃ is composed of 3 types of elements, namely Ca, C and O
The amounts of each of these elements in the compound CaCO₃:
So the number of oxygen atoms = 3
mass of Oxygen :

The answer is C :
It controls the entry and exit of substances.
The answer would most likely be true.
Answer:
liquid oxygen is highly flammable
Explanation:
near any source of heat. liquid oxygen can explode to flames thus being hazardous