In a certain compound of copper and oxygen, a sample weighing 0.5424g contains 0.4831 g of Cu. How many moles of Cu in the sample? How many grams of Oxygen and how many moles of Oxygen are there in the sample? What is the mole ratio of Cu/O in the sample? What is the formula of the oxide and the molar mass of thye copper oxide?
0.008 mol
To determine the number of moles of Cu in the sample, we can use the formula:
moles = mass / molar mass
First, let's calculate the number of moles of Cu in the sample:
moles of Cu = 0.4831 g / atomic mass of Cu
The atomic mass of Cu is 63.546 g/mol. Plugging in the values:
moles of Cu = 0.4831 g / 63.546 g/mol
moles of Cu = 0.0076 mol
So, there are 0.0076 moles of Cu in the sample.
To find the number of grams of oxygen and moles of oxygen in the sample, we can subtract the mass of Cu from the total mass of the sample:
mass of oxygen = mass of sample - mass of Cu
mass of oxygen = 0.5424 g - 0.4831 g
mass of oxygen = 0.0593 g
To calculate the number of moles of oxygen, we can use the formula mentioned earlier:
moles of oxygen = mass of oxygen / molar mass of oxygen
The molar mass of oxygen is 16.00 g/mol, so:
moles of oxygen = 0.0593 g / 16.00 g/mol
moles of oxygen = 0.0037 mol
Therefore, there are 0.0593 grams and 0.0037 moles of oxygen in the sample.
To determine the mole ratio of Cu/O in the sample, we need to compare the number of moles of each element. The ratio is given by:
mole ratio = moles of Cu / moles of O
mole ratio = 0.0076 mol / 0.0037 mol
mole ratio ≈ 2.05
Thus, the mole ratio of Cu/O in the sample is approximately 2.05.
Now, to find the formula of the oxide and the molar mass of copper oxide, we need to use the mole ratio and the atomic masses of Cu and O.
Since the mole ratio is approximately 2.05, we can assume that the empirical formula of the oxide is Cu2O.
To calculate the molar mass of copper oxide, we add the atomic masses of copper (Cu) and oxygen (O) in the empirical formula:
molar mass of Cu2O = (2 x atomic mass of Cu) + atomic mass of O
molar mass of Cu2O = (2 x 63.546 g/mol) + 15.999 g/mol
molar mass of Cu2O ≈ 143.137 g/mol
Therefore, the formula of the oxide is Cu2O, and the molar mass of copper oxide is approximately 143.137 g/mol.