2C 2 H 6 +7O 2 ***>4CO 2 +6H 2 O if 7.0 g of C 2 H 6 react with 18 g of O 2 , how many grams of water will be produced

grams H₂O produced = 8.7 grams

Explanation:

Given 2C₂H₆(g) + 7O₂(g) => 4CO₂(g) + 6H₂O(l)

               7g           18g                             ?g

Plan => Convert gms to moles => determine Limiting reactant => solve for moles water => convert moles water to grams water

Moles Reactants

moles C₂H₆ = 7g/30g/mol = 0.233mol

moles O₂ = 18g/32g/mol = 0.563mol

Limiting Reactant => (Test for Limiting Reactant)  Divide mole value by respective coefficient of balanced equation; the smaller number is the limiting reactant.

moles C₂H₆/2 = 0.233/2 = 0.12

moles O₂/7 = 0.08

Limiting Reactant is O₂

Moles and Grams of H₂O:

Use Limiting Reactant moles (not division value) to calculate moles of H₂O.

moles H₂O = 6/7(moles O₂) = 6/7(0.562) moles H₂O = 0.482 mole H₂O yield

grams H₂O = (0.482mol)(18g·mol⁻¹) = 8.7 grams H₂O