Question

chemistry 20 stoichiometry quiz
name: edesam
multiple choice

1. how many moles are in 76.2 g of nickel (iii) oxide?

□ 2.17
□ 0.461
□ 1.25×10⁴
□ 1.12

Explanation:

Step1: Find nickel(III) oxide formula and molar mass

The formula of nickel(III) oxide is $Ni_2O_3$. The molar mass of $Ni$ is approximately $58.69\ g/mol$ and of $O$ is approximately $16\ g/mol$. So the molar mass of $Ni_2O_3$ is $2\times58.69 + 3\times16=117.38+ 48 = 165.38\ g/mol$.

Step2: Calculate moles

Use the formula $n=\frac{m}{M}$, where $m = 76.2\ g$ (mass of nickel(III) oxide) and $M=165.38\ g/mol$ (molar mass). So $n=\frac{76.2}{165.38}\approx0.461\ mol$.

Answer:

0.461