a.
| 2Zn | + O2 | → 2ZnO | |
| \[m\] | ①\[12\mathrm{g}\] | ④\[15\mathrm{g}\] | |
| \[n\] | ②\[0,18354237\mathrm{mol}\] | ③\[0,18354237\mathrm{mol}\] |
① \(m_\mathrm{Zn} = 12\mathrm{g}\)
② \(n_\mathrm{Zn} = \frac {m_\mathrm{Zn}}{M_\mathrm{Zn}} = \frac {12\mathrm{g}}{65,38\frac {\mathrm{g}}{\mathrm{mol}}} = 0,18354237\mathrm{mol}\)
③
\(n_\mathrm{Zn}:n_\mathrm{ZnO} = 1:1 \\ n_\mathrm{ZnO} = n_\mathrm{Zn} = 0,18354237\mathrm{mol}\)
④ \[\begin{aligned} m_\mathrm{ZnO} &= M_\mathrm{ZnO} \cdot n_\mathrm{ZnO} = (65,38 + 16,00)\frac {\mathrm{g}}{\mathrm{mol}} \cdot 0,18354237\mathrm{mol} = \\ &= 14,9366779\mathrm{g} ≈ 15\mathrm{g}\end{aligned}\]
b.
| 2Zn | + O2 | → 2ZnO | |
| \[m\] | ①\[6,5\mathrm{g}\] | ④\[1,6\mathrm{g}\] | |
| \[n\] | ②\[0,09941878\mathrm{mol}\] | ③\[0,04970939\mathrm{mol}\] |
① \(m_\mathrm{Zn} = 6,5\mathrm{g}\)
② \(n_\mathrm{Zn} = \frac {6,5\mathrm{g}}{65,38\frac {\mathrm{g}}{\mathrm{mol}}} = 0,09941878\mathrm{mol}\)
③
\(n_\mathrm{Zn}:n_\mathrm{O_2} = 2:1 \\ n_\mathrm{O_2} = \frac {1}{2}n_\mathrm{Zn} = \frac {1}{2} \cdot 0,09941878\mathrm{mol} = 0,04970939\mathrm{mol}\)
④ \[\begin{aligned}m_\mathrm{O_2} &= M_\mathrm{O_2} \cdot n_\mathrm{O_2} = (16,00 \cdot 2)\frac {\mathrm{g}}{\mathrm{mol}} \cdot 0,04970939\mathrm{mol} = \\ &= 1,59070052\mathrm{g} ≈ 1,6\mathrm{g}\end{aligned}\]
