Question

What is the molarity of a 250ml KCl solution made by diluting 175mL of a 3.00 M solution?

Answer 1

2.1 M

Step-by-step explanation:

The dilution equation is
`M_(s) V_(s) = M_(d) V_(d)`.

`M_(s)` = the molarity of the sock solution

`V_(s)` = the volume of the sock solution

`M_(d)` = the molarity of the diluted solution

`V_(d)` = the volume of the diluted solution

The stock solution would be what is doing the diluting, so "175 mL of a 3.00 M solution". So
`M_(s)` = 3.00 M. Then: Converting 175 mL to liters:
`175 mL * (1 L)/(1000mL) = 0.175 L` (This is
`V_(s)`)

And converting 250 mL KCl to liters:
`250 mL * (1 L)/(1000mL) = 0.250 L` (This will be
`V_(d)`)

Then, we plug in our given into the dilution equation, resulting in:

`3.00 M * 0.175 L = M_(d) * 0.250 L` (divide both sides by 0.250 L, in order to get
`M_(d)` by itself)

`(3.00 M * 0.175 L)/(0.250 L) = M_(d)`

`M_(d) = 2.1 M`

So, the molarity of 250 mL KCl made by diluting 175 mL of a 3.0 M solution would be 2.1 M (mol/L).

Hopefully this helped you understand the topic a little bit better. I just finished molarity and dilutions in Chemistry last week. Good luck!