Question

Robin and Alex are discussing how water molecules form when hydrogen and oxygen atoms combine. Robin writes the following chemical equation to explain the formation of water. However, Alex has a different opinion and suggests that the chemical reaction can be better represented by using the equation below. Why does Alex’s equation better represent the reaction?
A.
For every two molecules of water formed, one hydrogen atom is needed.
B.
For every two molecules of water formed, two hydrogen atoms are needed.
C.
The number of oxygen atoms is the same before and after the reaction.
D.
The amount of product formed should be more than the amount of reactants involved.

Answer 1

Answer:

Option C. The number of oxygen atoms is the same before and after the reaction.

Explanation:

When hydrogen combine with oxygen, water is formed. According to law of conservation of matter, matter cannot be created nor destroyed during a chemical reaction. So according to this law, the amount of reactants is equal to the amount of product produced after a chemical reaction and the number of oxygen atoms is the same before and after the reaction.

Answer 2

Answer:

C.

The number of oxygen atoms is the same before and after the reaction.

Explanation:

4H + O2 = 2H2O

The above chemical equation shows that the molecules of Oxygen at the reactant side is equal to that at the product side.