Chemistry!

[ecrs2300]

Aspirin is made for medical uses. The equation is..

C7H6O3 + C4H6O3 --> C9H8O4 + CH3COOH
salicylic aspirin

Calculate the maximum of aspirin that could be made from 2.00g of salicylic acid.

The relative formula mass (Mr) of salicylic acid, C7H6O3, is 138
The relative formula mass (Mr) of aspirin, C9H8O4, is 180

Any help greatly received! Thanks!

[DTCwordfan]

I can feel a headache coming on.................ask Molly.

[mollykins]

I won't tell you the answer but;

You have to work out how many moles 2g of the S.Acid is and then work out the mass of that amount of moles makes of the asprin (and that's it, but with some things like this more than one mole of something makes a different amount of moles of something else so you might have to half/ double an answer for example.)

Hope that helps. BTW i'm doing a-level chem.

[mollykins]

Geddit now ecrs?

1) work out how many moles 2g of s.acid is.

2) work out how many grams of asprin is in that amount of moles.

(if I didn't make that clear enough to start with)

[ecrs2300]

Yes, thanks molly! i shall come back to you if i get stuck! Thank you!

[mollykins]

Worked it out? Sometimes with wordier questions is hard to work out what they're asking you and how you're meant to do it with the info you have. But if you know your formulae you can look at what you've got, what you can work out from that, and how you use that number with any other info you have to find the answer, almost every time with these kinds of questions you need to do two calculations in this case it's the amount of moles in the first thing and then you use the answer to that to work out the second thing ie the grams of asprin.

[divlong]

You don't actually need to work out the number of moles. The number of molecules of aspirin is the same as the initial number of molecules of salicylic acid. So all you need is 2g * 180 / 138 = 2.609g.