Calculate the molar mass of Cu2O and the % by weight of Cu in Cu2O.
The Correct Answer and Explanation is:
To calculate the molar mass of Cu2O and the percentage by weight of Cu in Cu2O, let’s break it down step by step:
Step 1: Determine the Atomic Masses
The atomic mass of copper (Cu) is approximately 63.55 g/mol, and the atomic mass of oxygen (O) is 16.00 g/mol.
Step 2: Calculate the Molar Mass of Cu2O
In Cu2O, there are 2 copper (Cu) atoms and 1 oxygen (O) atom. The molar mass of Cu2O can be calculated by adding the atomic masses of all the elements in the formula:
- 2 × 63.55 g/mol (for Cu) = 127.10 g/mol
- 1 × 16.00 g/mol (for O) = 16.00 g/mol
So, the molar mass of Cu2O is:Molar Mass of Cu2O=127.10 g/mol+16.00 g/mol=143.10 g/mol\text{Molar Mass of Cu2O} = 127.10 \, \text{g/mol} + 16.00 \, \text{g/mol} = 143.10 \, \text{g/mol}Molar Mass of Cu2O=127.10g/mol+16.00g/mol=143.10g/mol
Step 3: Calculate the Percentage by Weight of Cu in Cu2O
Now, we calculate the percentage by weight of copper (Cu) in Cu2O. This can be done by dividing the total mass of copper in the formula by the molar mass of Cu2O and multiplying by 100.
- The mass of copper (Cu) in Cu2O is 127.10 g/mol (from the 2 Cu atoms).
- The molar mass of Cu2O is 143.10 g/mol.
The percentage by weight of copper in Cu2O is:% Cu=(127.10 g/mol143.10 g/mol)×100=88.8%\% \, \text{Cu} = \left( \frac{127.10 \, \text{g/mol}}{143.10 \, \text{g/mol}} \right) \times 100 = 88.8\%%Cu=(143.10g/mol127.10g/mol)×100=88.8%
Final Answer:
- The molar mass of Cu2O is 143.10 g/mol.
- The percentage by weight of Cu in Cu2O is 88.8%.
This means that in every mole of Cu2O, 88.8% of the mass is due to copper.
