Answer to Question #136478 in Inorganic Chemistry for jacquez

Question

1. Hydrogen and oxygen react chemically to form water. How much water would form if 19.2 grams of hydrogen reacted with 40.1 grams of oxygen? (H2 + O2 → H2O) 

Answer 1

Balanced reaction:

2H₂ + O₂ → 2H₂O

M(H₂) = 2 g/mol

M(O₂) = 32 g/mol

$n = \frac{m}{M}$

n(H₂) $= \frac{19.2}{2} = 9.6 \;mol$

n(O₂) $= \frac{40.1}{32} = 1.25 \;mol$

Proportion from the reaction:

H₂: O₂ = 2:1

Proportion from the reactants masses:

H₂: O₂ = 9.6:1.25

O₂ is the limiting reactant that will completely react.

n(H₂O) = 2n(O₂) $= 2\times1.25 = 2.5\; mol$

M(H₂O) = 18 g/mol

m(H₂O) $= n\times M = 2.5\; mol\times 18\;g/mol = 45\; g$

Answer: 45 g