Question

A chemist prepares a solution by dissolving 0.3 mole of CaCl2 in enough water to make 1000 mL of solution. What is the molar concentration of chloride ions?
0.6 M
0.4 M
0.1 M
0.2 M
0.3 M

Answer 1

@abb0t @rvc

Answer 2

@aaronq

Answer 3

@abb0t @DoShKa_SyRiA @Frosty_Flow

Answer 4

Concentration is given by units, \(\sf \large \frac{mol}{L}\)
That means you will be dividing moles by Litres of solution.

Answer 5

But there will be double the number of moles in water of Chloride , right ?

Answer 6

0.6 / 1 ?

Answer 7

It is moles of solute per litres of solution.

Answer 8

But we have to find the molar concentration of Chloride ions .

When it will dissolve , there will be two moles of Cl2 for every one mole of CaCl2 .

Therefore Moles of Solute = 0.3 * 2 = 0.6
1000 ml = 1L.

0.6 / 1

Answer 9

@abb0t

Answer 10

You wil basically have: \(\sf CaCl_{2} \rightarrow Ca^{2+} + 2~Cl^- + H_2O \)

Answer 11

As you can see, 2(0.3) moles = 0.6 moles. Then divide by litres.

Answer 12

So 0.6 M , right ?

Answer 13

Thanks

Answer 14

Had one more question @abb0t ,
Consider the force of interaction between a cation and an anion. Which of the following does not make the force more attractive? (Recall Coulomb’s law has the formula F = kq1q2/(εr2)
*Change the charge on the anion so that it is less negative
*Decrease the distance between the ions
*Increase the charge on the cation so that it is more positive
*Decrease the dielectric constant of the fluid between the ions
*All of the other answer choices listed make the force more attractive

Answer 15

D. The dielectric constant does not affect the force of attraction.