The number of grams of methane that it take to make 16.5 g of H2o is 7.33 g of methane
calculation
CH₄ + 2O₂ → CO₂ +2H₂O
step 1: find the moles of H₂O
moles = mass÷ molar mass
from periodic table the molar mass of H₂O= [(1 x2) +16] = 18 g/mol
moles = 16.5 g÷ 18 g/mol =0.9167 moles
step 2 : use the moles ratio to determine the moles of CH₄
CH₄ :H₂O is 1:2 therefore the moles of CH₄ = 0.9167 x 1/2 =0.4584 moles
Step 3: find mass of CH₄
mass = moles x molar mass
from periodic table the molar mass of CH₄ = [12+ (1 x4)] = 16 g/mol
mass = 0.4584 moles x 16 g/mol = 7.33 g