Question

How many grams are there in `7.50 x 10^23` molecules of `H_2SO_4`?

Answer 1

Well, how many grams in `6.022xx10^23` `"sulfuric acid molecules"`?

Explanation:

It is a fact that such a quantity has a mass of `98.08*g`. Why? Because `6.022xx10^23` particles SPECIFIES a molar quantity. And we know (or can calculate) that sulfuric acid has a molar mass of `98.08*g`...

And so we take the quotient....

`(7.5xx10^23*"sulfuric acid particles")/(6.022xx10^23*"sulfuric acid particles"*mol^-1)xx98.08*g*mol^-1=122*g`...

Answer 2

`122.5g`

Explanation:

• 1st, we need to convert `7.50`x`10^23`molecules into moles

`7.50`x`10^23`molecules x `(1mol)/(6.02x10^23)` =`1.25mol`

• Now we convert `1.25mol` to grams `(g)`

`1.25cancel(mol` x `(98g)/(1cancel(mol)` = `122.5g`

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

`H_2` = `1g` x `2` = `2g`

`S` = `32g`

`O_4` = `16g` x `4` = `64g`

`2g` + `32g` + `64g` = `(98g)/(1mol)`