To find the percent composition by mass of each element in the compound SnO₂ (tin(IV) oxide), we need to calculate the molar mass of the compound and then determine the mass percent of each element.
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Calculate the molar mass of SnO₂:
- The molar mass of tin (Sn) is approximately 118.71 g/mol.
- The molar mass of oxygen (O) is approximately 16.00 g/mol.
The formula for SnO₂ indicates that there is 1 tin atom and 2 oxygen atoms: \[ \text{Molar mass of SnO}_2 = (1 \times 118.71 , \text{g/mol}) + (2 \times 16.00 , \text{g/mol}) \]
\[ = 118.71, \text{g/mol} + 32.00, \text{g/mol} = 150.71, \text{g/mol} \]
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Calculate the mass percent of Sn: \[ \text{Mass percent of Sn} = \left( \frac{\text{mass of Sn}}{\text{molar mass of SnO}_2} \right) \times 100 \] \[ = \left( \frac{118.71, \text{g/mol}}{150.71, \text{g/mol}} \right) \times 100 \approx 78.7% \]
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Calculate the mass percent of O: \[ \text{Mass percent of O} = \left( \frac{\text{mass of O}}{\text{molar mass of SnO}_2} \right) \times 100 \] \[ = \left( \frac{32.00, \text{g/mol}}{150.71, \text{g/mol}} \right) \times 100 \approx 21.3% \]
Thus, the percent composition by mass of Sn and O in SnO₂ is approximately:
- Tin (Sn): 78.7%
- Oxygen (O): 21.3%