Answer:
0.252 g O₂
Explanation:
Step 1: Find RxN
O₂ (g) + Element X (s) → ZnO (s)
O₂ (g) + Zn (s) → ZnO (s)
Step 2: Balance RxN
We need 2 oxygens on both sides.
- We would also need 2 zincs on both sides if we balance oxygen
O₂ (g) + 2Zn (s) → 2ZnO (s)
Step 3: Define
Given - 1.28 g ZnO
Find - x g O₂
Molar Mass of Zn - 65.39 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of O₂ - 2(16.00) = 32.00 g/mol
Molar Mass of ZnO - 65.39 + 16.00 = 81.39 g/mol
Step 4: Stoichiometry
[tex]1.28 \hspace{3} g \hspace{3} ZnO(\frac{1 \hspace{3} mol \hspace{3} ZnO}{81.39 \hspace{3} g \hspace{3} ZnO} )(\frac{1 \hspace{3} mol \hspace{3} O_2}{2 \hspace{3} mol \hspace{3} ZnO} )(\frac{32.00 \hspace{3} g \hspace{3} O_2}{1 \hspace{3} mol \hspace{3} O_2} )[/tex] = 0.251628 g O₂
Step 5: Simplify
We are given 3 sig figs.
0.251628 g O₂ ≈ 0.252 g O₂
