Basic Chemistry

[dazedgonebye]

I need to make up a 40% solution of powdered citric acid in water, for use in printing cyanotypes.
Anyone know how to accomplish this?

I think I could manage this with 2 liquid components, but with a powder and a liquid?

 

[RichC]

Per cent solutions are typically by weight, so 100 ml of 40% citric acid solution will contain 40 g of citric acid and 60 g (= 60 ml, conveniently) of water.

 

[dazedgonebye]

That's handy. Now I just need some way of weighing in grams.
I have a scale, but it reads in grains. I'm sure I can find that conversion.

 

[dazedgonebye]

1 gram = 15.43 grains.
Cool, I'm good to go.

 

[RichC]

That's handy. Now I just need some way of weighing in grams.

Actually, since the weights are ratios, the units don't matter - for example, 8 oz of acid and 12 oz (= 20 oz) would work just as well.

Vaguely heard of a grain, but I'm mainly metric. (The UK changed over to metric slowly over a couple of decades starting in the 1970s, and Imperial units are still widely used. Unfortunately, as it changed when I was fairly young, I'm caught between the two: for example, if it's freezing out, I think of temperatures in centigrade, but if I'm hot I think in Fahrenheit; I cook using grams, but weigh myself in stones! And I find I can't swap between them easily : I know exactly what 70 F feels like, but 45 F means nothing! All very confusing!! 😕)

 

[dazedgonebye]

Grains is Troy measure...still used in balistics for bullet and gunpowder weights.

A fairly standard load for a .45 ACP round is a 230 grain bullet over about 6 grains of powder (depending on the make).