How to solve a pH problem!

[chemstudent]

A water sample has a pH of 8.21 and a total ca2+ concentration of 143 ppm.

a. What are the molar concentrations of CO32- and HCO3-?
b. What is the total alkalinity of the water?

Thank you!

 

[boostnbuds]

lol i assume your a student of chemistry, so i would suggest asking your proffesor.

 

[H3D]

I am not sure enough information was giving to solve the problem.

 

[chemstudent]

I transcribed this problem word-for-word and this is all I was given.
I have the following equations relating ca2+, CO32- and HCO3-.

1..... CO2(g)+H2O(aq)<=>H2CO3(aq)

2..... H2CO3<=>H+ +HCO3-

3..... CaCO3(s)<=>Ca2+ + CO32-

4..... CO32- + H2O<=>HCO3- + OH-

These equations are used in conjunction with Ka, Kb, Kw, Ksp values which are not given in the question. Hope this info rings a bell for somebody
Thanks, everybody, for your help!

 

[jpappy789]

Well H+ ions mean more acidic and hydroxide (OH-) ions are basic but thats all I got right now...I havent gotten to pH in chem yet this year...

 

[chunkoblue]

I think the important chemical equilibrium in this problem would be:
HCO3- <=> H+ + CO3(-2)

Are you allowed to look up the Ka for this equation to solve the problem?

 

[H3D]

I think the important chemical equilibrium in this problem would be:
HCO3- <=> H+ + CO3(-2)

Are you allowed to look up the Ka for this equation to solve the problem?

Ka = 4.30×10−7 mol/L

 

[boostnbuds]

lol ur avatar says ur snails are breading.

 

[shaner9999]

did you ever get the answer for this question?

chem student needing help. what was the final answer?

 

[jm1212]

i smell a homework problem...