If the reaction produced 15.5 g CO2, how many grams of heptane were burned?

5 g of heptane were burned.

Explanation:

Given dа ta:

Mass of CO₂ produced = 15.5 g

Mass of heptane burned = ?

Solution:

Balance chemical equation:

C₇H₁₆ + 11O₂ →7CO₂ + 8H₂O

First of all we will calculate the moles of CO₂ produced.

Number of moles = mass / molar mass

Molar of CO₂ = 44 g/mol

Number of moles = 15.5 g / 44 g/mol

Number of moles = 0.3523 mol

Now we will compare the moles of CO₂ and C₇H₁₆ from balance chemical equation

CO₂ : C₇H₁₆

7 : 1

0.3523 : 1/7 * 0.3523 = 0.05 mol

Mass of C₇H₁₆:

Number of moles = mass / molar mass

Mass = number of moles * molar mass

Mass = 0.05 mol / 100 g/mol

Mass = 5 g