[Richeyyy]

I have a glass bottle of HCl which says it's 36.46g/mol. I need to have 13g of it in my beaker. What is the formula to calculate how much I need of this HCl solution if I need 13g?

[Richeyyy]

what is that g/mol used for anyway? is it used to calculate concentration or something?

[Borek]

g/mol is just a molar mass and is a property of the substance itself. Concentration is property of the solution - if you don't have it, you can't calculate anything.

[Richeyyy]

oh, I see I see, well the concentration is 35-38% and molar mass is 36.46g/mol, what can I calculate using these two?

[Orcio_87]

@Richeyyy Concentration is in the range 35- 38 %, and you need only 13 g. This means you need 34- 37 g of acid.

However - pouring conc. HCl on a scale can damage the scale.

Instead - it is better to use the pipette and admeasure respective volume.

If only you would know the density...

[Richeyyy]

Eh nah it's fine I'm pretty slow and careful when it comes to safety, just slowly pour stuff into the beakers and always have some baking soda (even better max concentration baking soda solution) to neutralize HCl in case something goes wrong. Interesting, I see you didn't use g/mol thing to calculate how much of solution I need at all. Is there anything else useful I can calculate if I have g/mol value and the concentration value?

[Orcio_87]

I see you didn't use g/mol thing to calculate how much of solution I need at all. Is there anything else useful I can calculate if I have g/mol value and the concentration value?

Yes, you can calculate quantity - how many HCl "molecules" are present in 1 gram or 1 mL of the acid. This is useful in term of calculation of the pH.

[Richeyyy]

awesome, thanks for the info!

[Richeyyy]

I guess I can also calculate stoichiometric ratios as well if I know how many molecules are in a specific amount of some kind of substance or solid