Question

If i have 340mL of a 1.5 M NaBr solution, What will the concentration be for 1000mL?

Answer 1

0.51M

Step-by-step explanation:

Given parameters:

Initial volume of NaBr = 340mL

Initial molarity = 1.5M

Final volume = 1000mL

Unknown:

Final molarity = ?

Solution;

This is a dilution problem whereas the concentration of a compound changes from one to another.

In this kind of problem, we must establish that the number of moles still remains the same.

number of moles initially before diluting = number of moles after dilution

Number of moles = Molarity x volume

Let us find the number of moles;

Number of moles = initial volume x initial molarity

Convert mL to dm³;

1000mL = 1dm³

340mL gives
`(340)/(1000)` = 0.34dm³

Number of moles = initial volume x initial molarity = 0.34 x 1.5 = 0.51moles

Now to find the new molarity/concentration;

Final molarity =
`(number of moles)/(Volume)` =
`(0.51)/(1)` = 0.51M

We can see a massive drop in molarity this is due to dilution of the initial concentration.