Question

A sample of a compound made entirely from copper and oxygen was found to have a total mass of 0.143 g the mass of copper in the compound was found to be 0.1271 g calculate the mass of oxygen in the same. Also, Calculate the number of moles of oxygen in the sample. Please help!! Thank you in advance.

Answer 1

Mass of Oxygen: 0.0159 grams

Moles of Oxygen: 9.94x10^-4

To find the mass of oxygen, subtract the mass of copper from the total mass.

`0.143-0.1271=0.0159`

There are 0.0159 grams of Oxygen.

To find how many moles there are, divide the given amount of oxygen by the molar mass (atomic mass) of oxygen because that mass is the same as one mole of oxygen.

Molar mass of Oxygen: 16.00

`0.0159/16.00=9.94*10^(-4)`

There are 9.94*10^-4 moles of Oxygen.