If the reaction produced 15.5 g co2, how many grams of heptane were burned?

5 g of heptane were burned.

Explanation:

Given data:

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

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