Question

How many grams are there in 7.50 x 10^23 molecules of H2SO4?

Answer 1

Answer: 122.5g

1st, we need to convert 7.50x1023molecules into moles

7.50x1023molecules x 1mol6.02x1023 =1.25mol

Now we convert 1.25mol to grams (g)

1.25mol x 98g1mol = 122.5g

Note, when converting to grams, its gram formula mass / 1mol. The formula mass is all the element's masses added together

H2 = 1g x 2 = 2g
S = 32g
O4 = 16g x 4 = 64g
2g + 32g + 64g = 98g1mol

Answer 2

1) Find number of moles H2SO4.

1 mole is 6.02*10²³ molecules.

7.50*10²³ *1 mol/6.02*10²³ = 7.50/6.02 moles of H2SO4

2) Find mass of 1 mole H2SO4

M(H2SO4) =2* 1.0 + 32.1+4*16.0= 98.1 g/mol

3) Find mass of 7.50/6.02 moles of H2SO4.

7.50/6.02 mol H2SO4 * 98.1 g/1 mol H2SO4≈ 122 g

Answer is 122 g.