[carter200]

2 HCl (aq) + 1 Mg(OH)2 (s)   --> 2 H2O (L) + 1 MgCl2 (aq)

What is the concentration of magnesium chloride if 310 mL of 0.10 M HCl reacts with 5.00 g of magnesium hydroxide?


1 H3PO4 (aq) + 3 LiOH (aq)  --> 3 H2O (L) + 1 Li3PO4 (aq)

If 100 mL of 0.25 M H3PO4 reacts with 230 mL of LiOH, what is the concentration of LiOH?

What volume of 0.15 M phosphoric acid will react with 200 mL of 3.6 M LiOH?

What mass of lithium phosphate is made from 165 mL of 0.72 M lithium hydroxide?



Sorry for all the questions, but I've been struggling to find the formulas or what I'm supposed to do.

[Babcock_Hall]

It is a forum rule that you must show us your attempt before we can help you.  Can you, for example, show us a formula that you think is not the right one and why you think that?

[cosmonaut]

Seeing how the poster is struggling with starting out the problem.

In the first problem you are given a volume and molarity.  It is important to remember that Molarity is a concentration (moles/Liter).  This will allow you to find moles of HCl.  From here you need to remember how to convert moles HCl to  moles MgCl.  We can do this by utilizing the mole ratio.  This is provided by the balanced equation.  Finally, the question is asking for concentration which I'm assuming is molarity (moles/liter).

The second problem uses similar principles.  Just start with knowns and (slowly if necessary) tread along converting from vol. to moles then the next corresponding compound using mole ratio.

Hopefully that is enough of a start to get you going in the right direction. 

Also I was in high school chem once upon a time, don't be afraid to email your teacher (if possible).  I struggled, but now I'm a pro working in industry. I've been an astrochemist, analytical chemist, now a polymer chemist    .