Question

Find the mass in grams of 4.00 x 10^23 molecules of F2.

Answer 1

The question requires us to calculate the mass of 4.00 x 10^23 molecules of fluorine gas (F2).

To solve this question, we need to calculate the number of moles that corresponds to the amount of molecules given, calculate the molar mass of the molecule F2 and then relate the number of moles calculated with the molar mass.

First, let's obtain the number of moles that corresponds to 4.00 x 10^23 molecules of F2. To do that, we must keep in mind that 1 mol of a compound corresponds to 6.02 x 10^23 molecules of this compound:

6.02 x 10^23 molecules of F2 --------------- 1 mol of F2

4.00 x 10^23 molecules of F2 --------------- x

Solving for x, we have:

`x=\frac{(4.00*10^(23)\text{ molecules)}*(1\text{ mol)}}{(6.02\text{ }*10^(23)\text{ molecules)}}=0.664\text{ mol}`

Now that we have the number of moles (0.664 moles of F2), we need the molar mass of F2 to calculate the mass contained in 0.664 moles of this compound.

The atomic mass of F is 18.99 u. Then, the molar mass of the molecule that contain two atoms of F is (2 * 18.99) = 37.98 g/mol

Next, we calculate the mass of F2 contained in 0.664 mol of this gas, knowing that there are 37.98 g in each mol of this compound:

1 mol of F2 ------------ 37.98 g of F2

0.664 mol of F2 ----- y

Solving for y, we have:

`y=\frac{(0.664\text{ mol)}*(37.98\text{ g)}}{(1\text{ mol)}}=25.2\text{ g }`

Therefore, there are 25.2 g of F2 in 4.00 x 10^23 molecules of this gas.