Question

Gasohol is a fuel containing ethanol (C2H6O) that burns in oxygen (O2) to give carbon dioxide and water.    ( I need to understand the steps and how to get the solution)

If a car produces 77 g of CO2 , how many grams of O2 are used up in the reaction?

If you burn 136 g of C2H6O , how many grams of CO2 and H2O can be produced?

Answer 1

Balanced combution reaction is

C₂H₆O + 3O₂   2CO₂  + 3H₂O

molar mass of CO₂ = 44.01 gm / mole then 2 mole of CO₂ = 88.02 gm

molar mass of O₂ = 31.9988 gm / mole then 3 mole of O₂ = 95.9964 gm

According to reaction 2 mole of CO₂ produced when 3 mole of O₂ used that mean 88.02 gm of CO₂ produced when 95.9964 gm of O₂ used then for production of 77 gm of CO₂ required O₂ = 77 95.9964 / 88.02 = 83.98 gm

O₂ used in reaction = 83.98 gm

molar mass of C₂H₆O =46.06844 gm / mole

molar mass of CO₂ = 44.01 gm / mole then 2 mole of CO₂ = 88.02 gm

According to reaction 1 mole of C₂H₆O produce 2 mole of CO₂ that mean 46.06844 gm of C₂H₆O produce 88.02 gm of CO₂ then 136 gm of C₂H₆O produce = 136 88.02 / 46.06844 = 259.85 gm of CO₂

136 gm of C₂H₆O produce = 259.85 gm of CO₂

molar mass of C₂H₆O =46.06844 gm / mole

molar mass of H₂O = 18.01528 gm / mole then 3 mole of H₂O = 54.04584 gm

According to reaction 1 mole of C₂H₆O produce 3 mole of H₂O that mean 46.06844 gm of C₂H₆O produce 54.04584 gm of H₂O then 136 gm of C₂H₆O produce = 136 54.04584 / 46.06844 = 159.55 gm of H₂O

136 gm of C₂H₆O produce =159.55 gm of H₂O