Question

What is the molar mass (gram formula mass) for the compound sodium thiosulfate, `Na_2S_2O_3`?

Answer 1

I get `158.13 \ "g/mol"`.

Explanation:

To calculate the molar mass of sodium thiosulfate, `Na_2S_2O_3`, we need to find all the molar masses of the elements, and add them together.

`Na` has a molar mass of `23 \ "g/mol"`. So, `Na_2` will have a molar mass of `23 \ "g/mol"*2=46 \ "g/mol"`.

`S` has a molar mass of `32.065 \ "g/mol"`. So, `S_2` will have a molar mass of `32.065 \ "g/mol"*2=64.13 \ "g/mol"`.

`O` has a molar mass of `16 \ "g/mol"`. Therefore, ozone, or `O_3`, will have a molar mass of `16 \ "g/mol"*3=48 \ "g/mol"`.

Adding all the molar mass together, we find that the molar mass of sodium thiosulfate `(Na_2S_2O_3)` is:

`46 \ "g/mol"+64.13 \ "g/mol"+48 \ "g/mol"`

`=158.13 \ "g/mol"`.