Question

CH4+ 2O2= CO2+ 2H2O how many grams of CH4 were burned if 4.4 grams of CO2 was formed?

Answer 1

Task:

CH₄ + 2O₂ = CO₂ + 2H₂O how many grams of CH₄ were burned if 4.4 grams of CO₂ was formed?

Solution:

According to the chemical equation the amount of CO₂ produced is equal to the amount of CH₄ burned. (n(CO₂) = n(CH₄))

To calculate the mass of CH₄ we should find the number of moles of CH₄ first

n(mol) = m(g) / MW(g/mol)

The molar weight is calculated using atomic weights from the periodic table of elements.

MW(CO₂) = 12 + 2 · 16 = 44 g/mol

MW(CH₄) = 12 + 4 · 1 = 16 g/mol

As the number of moles is equal we can write

m(CO₂) / MW(CO₂) = m(CH₄) / MW(CH₄)

The equation for the mass of CH₄ is

m(CH₄) = m(CO₂) · MW(CH₄) / MW(CO₂) = 4.4 · 16 / 44 = 1.6 g

Answer: m(CH₄) = 1.6 g