Cl2 + F2 -> 2ClF

Calculate the mass of chlorine gas required to produce 5.00 x 10^-3g of chlorine monofluoride given an excess of fluorine gas.

I can do this with regular numbers but I don't understand how to do this with scientific notation!! >:O help please!

## Answers (1)

One mole of Cl2 will produce 2 moles of ClF

Molar mass of ClF is 35.5 + 19.0 = 54.5 g/mol so you need to generate 5.00*10^-3 / 54.5 = 9.17*10^-5 mol; you need half this, or 4.59*10^-5 moles of Cl2. The molar mass of Cl2 is 71.0 g/mol, so this is 4.59*10^-5 * 71.0 = 3.26*10^-3 g Cl2

Details of calculations:

5.00*10^-3 / 54.5 = (5.00/54.5)*10^-3 = 0.0917*10^-3 = 9.17*10^-5

9.17*10^-5 / 2 = (9.17/2)*10^-5 = 4.59*10^-5

4.59*10^-5 * 71.0 = 326 * 10^-5 = 3.26*10^-3