posted by Kim on .
In each of the following, determine how much solute (in g or mL) must be added to the correct quantity of water to make the given amount of solution at the correct concentration.
a)KI to make 50.0mL of a 0.50 M solutioon
b)12.0 M HCL to make 500 mL of a 1.0 M HCl
c)Sucrose (C12 H22 O11) to make 1.0 kg of a 5% sucrose (by mass) solution
d)1.0M NaCl to make 100.0 mL of 0.10 M NaCl
All of these are done strictly by definition. If you know the definition you should be able to do the problem.
Here is the first one. Try the others on your own.
M = moles/L.
Therefore, moles = M x L
We want 0.50M x 0.050 L = 0.025 moles.
moles = grams/molar mass and we rearrange to grams = moles x molar mass.
0.025 moles x molar mass KI = grams KI.
The others all follows this type solution (no pun intended) although they will vary somewhat depending upon the definition of the solution.