QuestionJune 10, 2025

7. According to the law of conservation of mass, how much zinc was present in the zinc carbonate?

7. According to the law of conservation of mass, how much zinc was present in the zinc carbonate?
7. According to the law of conservation of mass, how much zinc was present in the zinc carbonate?

Solution
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Answer

The mass of zinc in the zinc carbonate is calculated using the proportion of zinc in the compound. Explanation 1. Identify the Reaction Zinc carbonate decomposes into zinc oxide and carbon dioxide: \text{ZnCO}_3 \rightarrow \text{ZnO} + \text{CO}_2 . 2. Apply Conservation of Mass The mass of reactants equals the mass of products. If you know the mass of zinc oxide and carbon dioxide produced, sum them to find the initial mass of zinc carbonate. 3. Calculate Mass of Zinc Use the molar masses: Zn in ZnCO_3 is 65.38 g/mol, ZnCO_3 is 125.38 g/mol. The fraction of Zn in ZnCO_3 is \frac{65.38}{125.38}. 4. Determine Initial Zinc Mass Multiply the total mass of ZnCO_3 by the fraction of Zn to find the mass of zinc present.

Explanation

1. Identify the Reaction<br /> Zinc carbonate decomposes into zinc oxide and carbon dioxide: $ \text{ZnCO}_3 \rightarrow \text{ZnO} + \text{CO}_2 $.<br /><br />2. Apply Conservation of Mass<br /> The mass of reactants equals the mass of products. If you know the mass of zinc oxide and carbon dioxide produced, sum them to find the initial mass of zinc carbonate.<br /><br />3. Calculate Mass of Zinc<br /> Use the molar masses: Zn in ZnCO$_3$ is 65.38 g/mol, ZnCO$_3$ is 125.38 g/mol. The fraction of Zn in ZnCO$_3$ is $\frac{65.38}{125.38}$.<br /><br />4. Determine Initial Zinc Mass<br /> Multiply the total mass of ZnCO$_3$ by the fraction of Zn to find the mass of zinc present.
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