When 25.8 g of the alloy were dissolved in hydrochloric acid, 2.24 liters of hydrogen
| May 21, 2021 | education
When 25.8 g of the alloy were dissolved in hydrochloric acid, 2.24 liters of hydrogen were released. Mass fractions of copper and zinc (%) in this alloy are.
We have an alloy of copper and zinc. From this alloy, only zinc will react with an acid, therefore, all the hydrogen formed will be due to the zinc dissolution reaction.
We write the reaction equation: Zn + 2HCl = ZnCl2 + H2
We write the proportion to find exactly how much zinc is needed for this reaction:
2.24 – x
22.4 – 65
Whence x is equal to: x = 2.24 * 65 / 22.4 = 6.5 grams.
We find the percentage of zinc in the alloy by the ratio of their masses:
w Zn = 6.5 / 25.8 * 100% = 25.2%
w Cu = 100% – 25.2% = 74.8%
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