Question

how would set up this equation?
what mass of sucrose is needed to make 500ml of 2M solution?
Thanks!

Answer 1

Well we set up the equations we know and just substitute for unknown values :)
\[\large C=\frac{ n }{ V }\]
We know the concentration and volume, so we need to work with the amount of substance:
\[\large n=\frac{ m }{ M }\]
M is a constant so we get an expression with only 1 variable, the mass:
\[\large CV=n \to CV = \frac{ m }{ M }\]
\[\large CVM=m\]

Answer 2

what is this formula called?

Answer 3

You can call it stoichiometry if you like.

Answer 4

Or quantity calculations as I like to call it.

Answer 5

Just remember to convert the units so they fit, when doing the calculation. :)