I have this problem for homework:It's a chemistry problem, but it's really just basic algebra. The different units represent the different variables.How many mL of 1M acetic acid (C2H4O2) and .2 molal acetic acid need to be added to make 100 mL of vinegar (5% acetic acid)? Assume 1g/mL density of all solutions.
I started by listing everything that is given: density = 1g/mL; 1M solute = 1 mol solute/1 L solution; .2 molal solute = .2mol solute/1kg solvent (H2O); 60.052 g/mol solute; 18.000 g/mol solvent; .1L total solution. I am looking for the mL of solute in .1L of solution.
My first step was to use the Molarity to figure out the number of moles of the solute: 1M solute = .1 mol solute/.1L solution.
Then I used the number of moles to find the number of grams in the solution: .1mol x 60.052g/mol = 6.0052g solute.
Finally I converted the mass to volume using density: 6.0052g/(1g/mL) = 6.0052mL.
However I am pretty sure that this answer is wrong. When I insert the .1 mol of solute into the molality formula I get a totally different answer.
.2 molal = .1mol/500g -> 500gx.05/.95 = 26.315g -> 26.315g/(1g/mL) = 26.315mL.
Can anyone show me where I went wrong. It's possible that I may have just overthought it, but the answer just doesn't seem right to me.