Question

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

Answer 1

Answer:

54g

Explanation:

Answer 2

Answer:

54 g

Explanation:

Given data:

Mass of carbon = 18 g

Mass of CO₂ = 72 g

Mass of oxygen needed = ?

Solution:

Chemical reaction:

C + O₂     →       CO₂

according to law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

In given photosynthesis reaction:

6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

In a similar way,

C   +    O₂     →       CO₂

18 g +   X      = 72

X = 72 -18

X = 54 g

Thus, 54 g of O₂ are required.