The amount of copper was determined in 10 g sample. copper was precipitated, filtered and calcined, obtaining a final precipitate of 0.79 g oxide of copper , What % in copper mass in this sample?
Your post isn't complete. You don't say if the oxide is CuO or Cu2O. At lower temperatures (200-400 C) the product is CuO but at higher temperature (say1000 C) is Cu2O. I will assume the product is CuO and you can make the change if that is necessary.
0.79 g CuO x (atomic mass Cu/molar mass CuO) = ? = mass Cu in the 10 g sample.
Then % Cu in sample = (grams Cu from above/10)*100 = ?
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To determine the percentage of copper in the sample, we need to calculate the ratio of the mass of copper to the mass of the sample and then multiply it by 100.
Given:
Mass of the sample = 10 g
Mass of copper oxide precipitate obtained = 0.79 g
Step 1: Calculate the mass of copper in the sample.
The copper oxide is derived from copper, so we need to convert the mass of copper oxide to the mass of copper.
Since the atomic weight of copper (Cu) is 63.55 g/mol, and the formula for copper(I) oxide (Cu2O) is:
2Cu + O2 → 2Cu2O
The molar mass of Cu2O is 143.09 g/mol (63.55 g/mol of Cu x 2 + 16.00 g/mol of O).
Using the equation:
Mass of copper = Mass of copper oxide / (Molar mass of Cu2O / Molar mass of Cu)
Mass of copper = 0.79 g / (143.09 g/mol / 63.55 g/mol)
Mass of copper = 0.79 g / 2.25
Mass of copper = 0.351 g (rounded to three decimal places)
Step 2: Calculate the percentage of copper in the sample.
Percentage of copper = (Mass of copper / Mass of the sample) x 100
Percentage of copper = (0.351 g / 10 g) x 100
Percentage of copper = 3.51%
Therefore, the percentage of copper in the given sample is approximately 3.51%.