How many moles of o2 (molar mass = 32.00 g/mol) are needed to react completely with 52.0 l of ch4 (g) at stp to produce co2 and h2o? (molar mass of ch4 16.04 g/mol)
a. 11.6
b. 2.32
c. 4.64
d. 52.0

CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O (i)
at STP, 1 mol gas = 22.4 L gas. so you have 52.0 L / 22.4 L / mol = 2.32 mol CH4.
According to  the balanced reaction, you need 2 mol O2 for every 1 mol CH4. so you need 2 x 2.32 mol = 4.64 mol O2.

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