[mbckenny]

Hi,

I am wondering how to convert a 1% concentration caffeine solution into a g/ml value.


The method I used was as follows;

1ml of caffeine in 100ml, density of caffeine is 1.23 g/ml, therefore 1.23g of caffeine in 100 ml.

But my query is this, do I use 1 ml of caffeine in 100ml or do I assume it is 1 g of caffeine in 100 ml as I would get a different answer if i did that.

Cheers,
Mike

[Borek]

What kind of %? w/w? w/v?

[Jasim]

But my query is this, do I use 1 ml of caffeine in 100ml or do I assume it is 1 g of caffeine in 100 ml as I would get a different answer if i did that.

% in chemistry is ambiguous. You can have weight % or volume % as pointed out by Borek. They are both different as you have noticed.

[mbckenny]

What kind of %? w/w? w/v?

I believe it was w/w

[Borek]

If it was 1% w/w, then you have 1g in 100g of solution. As this is rather diluted, you may safely assume density of 1g/mL, so you have 1g in 100 mL.

Not that it would be much different in the %w/v case, but it is always better to spell it out.