In the reaction C + O2 → CO2, 18 g of carbon react with oxygen to produce 72 g of carbon dioxide. What mass of oxygen would be needed in the reaction? 18 g 54 g 72 g 90 g

The answer to your question is: 54 g

Explanation:

Reaction

C + O₂ ⇒ CO₂

Carbon mass = 18 g

Carbon dioxide mass = 72 g

To solve this question, we must remember the Lavoisier law of conservation of mass, that states that in an isolated of closed system, matter can not be created or destroyed.

This law states that the mass of the reactans must be equal to the mass of the products.

Then

Mass of reactants = 18 + ?

Mass of products = 72

So,

18 + x = 72

x = 72 - 18

x = 54 g of oxygen