Hi! i'm kinda having trouble getting this.. Don't understand it really

from

Ca(OH)2 + 2HCl-----> CaCl2 + 2H2O

How do i calculate Ca+?

:You need much more information.
1) do you mean the concentration of Ca+ ion?
2) is there excess HCl? What is given?

ok

It was from a titration/ stoichiometry lab i did

it was between 0.05 mol/dm^3 HCl and saturated Ca(OH)2

The Ca(0H)2 volumes used were

23.39, 22.49 and 20.78

What was the volume of the HCl?

How did you "titrate". At what point did the "titration" end?

the volume of the HCL was 20cm^3

the HCL was titrated against the Ca(OH)2.. we were determining the solubilty product of Ca(OH)2.

WE did the experiment 3 times
and these were the readings for the volumes of the Ca(OH)2 used

23.39, 22.49, 20.78

Ok. You know the moles of HCl used (concentration x volume) watch units.
There fore, the balanced equation tells you how many moles of Ca(OH)2 were used, so the concentration of the Ca+ ion is that number of moles /volume of total water solution (acid solution and acid solution)

check my thinking, I am not certain of your setup and procedure.

Your thinking is correct! To calculate the concentration of Ca+ ion, you need to determine the number of moles of Ca(OH)2 used and the total volume of the water solution. Here's how you can do it:

1. Calculate the moles of HCl used:
Moles of HCl = concentration of HCl x volume of HCl
Moles of HCl = 0.05 mol/dm^3 x 20 cm^3

Make sure the units of concentration and volume are consistent (dm^3 and cm^3 in this case), so you may need to convert the volume to dm^3.

2. Since the balanced equation tells us that 1 mole of Ca(OH)2 reacts with 2 moles of HCl, the moles of Ca(OH)2 used will be half of the moles of HCl:
Moles of Ca(OH)2 = Moles of HCl / 2

3. Determine the total volume of the water solution:
Total volume = volume of Ca(OH)2 + volume of HCl
Total volume = 23.39 cm^3 (or dm^3, if you converted previously) + 20 cm^3 (or dm^3)

4. Calculate the concentration of Ca+ ion:
Concentration of Ca+ = Moles of Ca(OH)2 / Total volume of solution

Now you have the concentration of Ca+ ion in the solution. Remember to check the units and convert them if necessary.