Question

a scientist studies the following chemical equation for the production of water.
2h₂ + o₂→2h₂o
what happens to the mass of the reactants during this chemical reaction?
a. mass of oxygen stays the same
b. mass of hydrogen doubles
c. mass of oxygen decreases
d. mass of hydrogen increases

Explanation:

Step1: Analyze the chemical reaction

In the reaction \(2H_2 + O_2
ightarrow2H_2O\), hydrogen (\(H_2\)) and oxygen (\(O_2\)) are reactants. As the reaction proceeds, hydrogen and oxygen react to form water (\(H_2O\)).

Step2: Consider the law of conservation of mass

According to the law of conservation of mass, mass is neither created nor destroyed in a chemical reaction. But for individual reactants, their masses change as they are consumed in the reaction.

• For oxygen (\(O_2\)): It is a reactant. As the reaction occurs, oxygen molecules react with hydrogen molecules. So the mass of oxygen decreases as it is being used up in the reaction to form water.
• For hydrogen (\(H_2\)): It is also a reactant. Its mass decreases as it reacts to form water, not doubles or increases.

Answer:

C. mass of oxygen decreases