Calculate the number of molecules of Freon-12 in 4.43 mg of Freon-12. What is the mass of chlorine in 4.43 mg of Freon-12?

Question

Freon-12 is used as a refrigerant in air conditioners and as a propellant in aerosol cans. Calculate the number of molecules of Freon-12 in 4.43 mg of Freon-12. What is the mass of chlorine in 4.43 mg of Freon-12?

Answer 1

So if we take a look at Freon-12, we can see that its chemical formula is CCl2F2. Therefore, we can see that the molar mass of Freon-12, or the mass of 1 mol of Freon-12, is equal to

1* 12g/mol +

2* 35.5g/mol +

2* 19g/mol = 121g/mol

Where the three molar masses I found were from Carbon, Chlorine, and Flourine respectively.

We can then set up an expression to find the numbers of molecules in 4.43mg of Freon-12

4.43mg Freon-12 *

1g/1000mg*

1mol/121g*

6.02*10^23 molecules/1mol = 2.20 * 10^19 molecules

We can see from looking at the molar ratios of Freon-12 that there are 2 Chlorine atoms for every 1 Freon-12 molecule. Therefore, we can see that for every 1 mole of Freon 12 there are 2 moles of Chlorine atoms.

We find the number of moles of the allotted Freon-12 by

4.43mg Freon-12 *

1g/1000mg*

1mol/121g* = .0000366 moles Freon-12

We then multiply it by 2 to get the # moles of Chlorine

.0000732 moles Cl * 35.5g/mol = .00260 grams of Cl