When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 20.4 g of carbon were burned in the presence of 66.2 g of oxygen, 11.8 g of oxygen remained unreacted. What mass of carbon dioxide was produced?

74.77 g

Explanation:

The equation for the reaction between carbon and Oxygen is given by;

C (s) + O₂ (g) → CO₂ (g)

We are given;

Mass of carbon 20.4 g

Mass of Oxygen is 66.2 g

Remaining mass of Oxygen after the reaction is 11.8 g

Therefore, Carbon is the rate limiting reagent since Oxygen was in excess.

We are required to calculate the mass of carbon dioxide produced.

Step 1: Moles of Carbon produced

Moles = Mass : Molar mass

Molar mass of carbon = 12.01 g/mol

Therefore;

Moles of Carbon = 20.4 g : 12.01 g/mol

= 1.699 moles

Step 2: Moles of carbon dioxide produced

From the equation, 1 mole of carbon reacts to produce 1 mole of carbon dioxide.

Therefore, the mole ratio of Carbon to carbon dioxide is 1 : 1

Thus, moles of carbon dioxide = Moles of carbon

= 1.699 moles

Step 3: Mass of carbon dioxide produced

Mass = Moles * Molar mass

Molar mass of carbon dioxide = 44.01 g/mol

Therefore;

Mass = 1.699 moles * 44.01 g/mol

= 74.77 g

Therefore, the mass of carbon dioxide gas produced is 74.77 g