Final answer:
To calculate the percent purity of the sample, you need to determine the mass of the pure zinc in the sample and compare it to the total mass of the sample. First, let's find the mass of hydrogen gas produced: 0.0764 g of H2 is obtained from 3.86 g of the sample. The percent purity of the sample is approximately 64.2%.
Step-by-step explanation:
To calculate the percent purity of the sample, we need to determine the mass of the pure zinc in the sample and compare it to the total mass of the sample. First, let's find the mass of hydrogen gas produced: 0.0764 g of H2 is obtained from 3.86 g of the sample. Next, we'll convert the mass of H2 to moles: 0.0764 g H2 x (1 mole H2/2.016 g H2) ≈ 0.0379 moles H2 Since the reaction is: Zn + H2SO4 → ZnSO4 + H2.
The moles of H2 produced is equal to the moles of Zn: 0.0379 moles Zn To find the percent purity, we can divide the mass of pure zinc by the total mass of the sample. The molar mass of Zn is 65.4 g/mol: 0.0379 moles Zn x 65.4 g/mol ≈ 2.48 g Zn Now we can calculate the percent purity: Percent Purity = (Mass of pure Zn / Total mass of sample) x 100 Percent Purity = (2.48 g Zn / 3.86 g sample) x 100 ≈ 64.2%.