Anonymous

# If there are 5.22*10^19 molecules of H2SO3, determine the number of oxygen atoms present?

Could someone help me with this? I know I have to use Avogadros number, but I dont know how to set up the problem.

b. Determine the mass, in grams, of 5.22*10^19 molecules of H2SO3

Could someone walk me through this as well? I appreciate the help, thanks

Relevance

Well, you have 5.22*10^19 molecules of H2SO3 and in a H2SO3 molecule there are 3 oxygen atoms, therefore you have 3*5.22*10^19 = 1.57*10^20 oxygen atoms present.

To determine the mass you need to first find the amount of H2SO3. Now the Avogadro constant comes in. To determine the amount of H2SO3 you have to see how many Avogadro numbers (how many moles) are there in your amount of molecules: 5.22*10^19/6.02*10^23 = 8.67*10^-5 moles.

Now you need to calculate the molar mass of H2SO3. That is 2*1.01 + 32.1 + 3*16.0 = 82.12 g/mol.

The mass of one mole of H2SO3 is 82.12 grams, so the mass of 8.67*10^-5 moles is 8.67*10^-5*82.12 = 7.12*10^-3 grams.

I hope that helps!

Have a nice day!

• Anonymous

Each molecule of H2SO3 has 3 atoms in it.

3 x (5.22 x 10^19 ) = 1.566 x 10^20

To find the mass, you must convert molecules to mole by using avogadro's number, and then covert to grams using molar mass.

5.22 x 10^19 x (1 mole / 6.02 x 10^23) x (82 grams / 1 mole) = 0.00711 grams.