A 20.8-g sample of fuel is burned in the presence of oxygen. As a result, 9.8 grams of carbon dioxide and 17.3 grams of water are produced and captured in containers. According to the law of conservation of matter, how much oxygen reacted with the fuel?

According to the law of conservation of matter, there should be 6.3 grams of oxygen reacted with the fuel

Explanation:

Step 1: Data given

Mass of fuel = 20.8 grams

In presence of oxygen, there is produced 9.8 grams of CO2 and 17.3 grams of water

According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

This means mass fuel + mass oxygen = mass carbon dioxide + mass water

Mass carbon dioxide = 9.8 grams

Mass water = 17.3 grams

Mass CO2 + H2O = 27.1 grams

Mass of the fuel = 20.8 grams

This means together with the mass of the fuel, the mass of the oxygen should be 27.1 grams

Mass oxygen = 27.1 - 20.8 = 6.3 grams

According to the law of conservation of matter, there should be 6.3 grams of oxygen reacted with the fuel

mass O2 = 6.3 g

Explanation:

X + O2 → CO2 + H2O

∴ X: sample of fuel

"the mass consumed of the reagents is equal to the mass of the products obtained" ... law of conservation of matter

⇒ gX + gO2 = gCO2 + gH2O

⇒ gO2 = gCO2 + gH2O - gX

⇒ gO2 = 9.8 gCO2 + 17.3 gH2O - 20.8 gX

⇒ gO2 = 6.3 gO2