help! chemistry problem.?

Question

which has the higher concentration of Cl ion:

0.2 M CaCl2 or 0.3 M KCl

I'd appreciate it if you tell me why. I'm confused about it and how to find out. thanks!

or

50 mL of 0.05 M KCL solution
or 200 mL of 0.04 M LiCl solution.

and why? i really don't understand.

Answer 1

CaCl2 --> Ca+2 + 2 Cl-

for every mole of CaCl2, we get 2 moles of Chloride

0.2 M gives 0.4 M in Chloride.

The 0.3 M KCl has only 0.3 M in both K+ and Cl-

50 mL of 0.05 M KCL solution contains:
0.05 moles/L of Chloride * 50 mL * 1.000 L/1000 mL = 0.0025 moles.

200 mL of 0.04 M LiCl solution contains:
0.04 moles/L * 200 mL * 1.000 L/ 1000 mL = 0.008 moles

0.008 > 0.0025 so the LiCl solution has more.

Answer 2

0.2 M CaCl2 is 0.2 M Ca++ and 0.4 M Cl-
0.3 M KCl is 0.3 M K+ and 0.3 M Cl-

As you can see, the CaCl2 has the higher conc. of Cl-

For the other two, one choice is 4 times the total amount of the other, even though that other is a little more concentrated.

M stands for mols/L. When you multiply a volume by a molarity, the result is an amount of moles. So in the second part of your problem, the way to solve is multiply the volume times the molarity and see which one has the higher number of moles.

Answer 3

0.2 M CaCl2 or 0.3 M KCl


each one mole CaCl2 when dissolved in water
provides one mole of Ca ions and two moles of Cl ions
0.2 M CaCl2 will provide (0.2)(2) = 0.4 moles of Cl ions

each one mole KCl when dissolved in water
provides one mole of K ions and one moles of Cl ions
0.3 M KCl will provide (0.3)(1) = 0.3 moles of Cl ions


The second part of your question is similuar to the first with an extra step.
Each salt will provide one Cl ion, however you have different conc and different volumes

recall :
50 ml = 0.050L
200ml = 0.200L
(M)(V) = moles

for 50 mL of 0.05 M KCL solution

( 0.05)(0.050) = 0.0025 moles of Cl ions

For 200 mL of 0.04 M LiCl solution
M)(V) = moles
( 0.04)(0.200) = 0.008 moles of Cl ions

(remember to use the correct charges on all ions)

Answer 4

In 1 mole CaCl2 you have 2 moles Cl-. In 0.2 mol you will have 0.4 mol of Cl-.

in 1 mole KCl you have 1 mole Cl-. In 0.3 mol KCl you have 0. mol Cl-.

So the answer should be the CaCl2.