Quick

50 grams of propane, c₃h₈, reacts with 120 grams of oxygen. what is the limiting reagent?

a) c₃h₈
b) o₂
c) co₂
d) h₂o

Limiting reagent is

B) O₂

Explanation:

From the balanced reaction.

C3H8 + 5O2 ==> 3CO2 + 4H2O

there are two reagents(C3H8 and O2)and the limiting one is the one that is used up before the end of the reaction .

C3H8 : 02 = 1:5

Given mass 50g of propane

Molar mass = (3×12 + 8×1) =44g/mol

Mole= 50/44 = 1.136mol.

Given 120g of oxygen gas

Molar mass =32g/mol

Mole = 120/32= 3.75mol.

From the ratio, for the complete reaction, oxygen needs 5× of propane = 5×1.136= 5.68mol , but it has less (3.75mol)

Therefore O₂ is the limiting reagent.