[tpac123]

Please help me out with any or all of these three questions as soon as possible! It would be so much appreciated.

The solubility of Ca(OH)2 in water is .185 g/100mL. What volume of .00250 M HCl is needed to neutralize 11.5 mL of a saturated Ca(OH)2 solution?

Iron (II) can be precipitated from neutral solutions by oxidizing it with MnO4-
MnO4^-(aq)+3Fe(OH)^+(aq)+2OH^-(aq)+2H2O(l)-->MnO2(s)+3Fe(OH)3(s)
What volume of 0.825 M MnO4^- is needed to completely react with 50.0 mL of 0.565 M Fe(II) (in mL)

Lactic acid causes burning of muscles during strenuous exercise. The hydrogen atom in the COOH group is acidic and it can be removed using base to form COO^- group. To determine the concentration of a solution of lactic acid, a chemist titrates 22.75 mL sample of it with 0.1010 M NaOH, and finds that 10.32 mL of titrant are required to reach the equivalence point. What is the concentration of the lactic acid solution in moles per liter? (M)

Again thank you in advance to anyone who can help, these are due tomorrow morning and I've tried and still cannot figure them out so any help would be appreciated so much.

[cseil]

You have to show some effort into solving these exercises. Come on.

What does "saturated" mean? How much Cu(OH)2 is there in 11.5mL of a saturated solution?
What does "neutralization" mean?

Let's start with the first question.

[tpac123]

For that one I cant figure out the correct answer, I found the molar mass of Cu(OH)2 to be 1284.58 g/mol. then multipled .185 by 11.5 to get 2.1275g divided by that molar mass to give me .00166mol...then what? is that right?

[Borek]

I found the molar mass of Cu(OH)2 to be 1284.58 g/mol

No, it is orders of magnitude wrong.

then multipled .185 by 11.5 to get 2.1275g

Watch the units - result is NOT in grams.

[tpac123]

what magnitude? and then I dont know what the units would be, because you have g/ml and then ml wouldnt that give grams? or is g/100mL something else? what do i do after that?

[Borek]

what magnitude?

You do understand the difference between hundreds and thousands? Or between tens and hundreds? When the difference between two numbers is about tenfold, we say they differ by order of magnitude.

and then I dont know what the units would be, because you have g/ml and then ml wouldnt that give grams? or is g/100mL something else? what do i do after that?

g/mL and g/100 mL is not the same thing. If there is 1 g in 100 mL, 1 mL doesn't contain 1 g, but 0.01 g.

You are right about trying to calculate how much Ca(OH)₂ was in the solution.

[Arkcon]

I found the molar mass of Cu(OH)2 to be 1284.58 g/mol.

Borek: said you were an order of magnitude off.  Do you really believe one mole of copper hydroxide weighs one and a quarter kilograms?  You wrote it, so  you must think so.  Its made of copper, and OH, that's practically water, twice.  If it weighed so much, what would a mole of water weigh?  Or the weight of half a mole of oxygen and a mole of H₂ gas?

Check that calculation, and when you do it again, consider what you're calculating, and be sure it makes sense.

[tpac123]

So then how should I write .185g/100ml? And I fixed the molar mass but still not sure how to get it to ml to what it is asking. It's 74.1g/mol