Question

The combustion of a sample of butune, C4H10 (lighter fluid), produced 2.46 grams of water.

Answer 1

Molar mass :

H₂O = 18.0 g/mol
O₂ = 32.0 g/mol

2 C₄H₁₀ + 13 O₂ = 8 CO + 10 H₂O

13 x 32.0 g O₂ ------------- 10 x 18.0 g H₂O
            ? g O₂ ------------- 2.46 g H₂O


Mass O₂ = 2.46 x 13 x 32.0 / 10 x 18.0

Mass  O₂ =1023.36 / 180

=> 5.68 g of O₂

hope this helps!