Question

200.0 mL of 0.778 M solution is diluted to 1.00 L. What is the molarity of the new solution? __________ M (Report your answer with the correct sig figs in units of moles/ L, M)

Answer 1

Answer:

The answer to your question is C₂ = 0.16 M

Explanation:

Data

Volume 1 = V1 = 200 ml

Concentration 1 = C1 = 0.778 M

Concentration 2 = C2 = ?

Volume 2 = 1 l

Formula

               C₁V₁  =  C₂V₂

Solve for C₂

               C₂ = C₁V₁ / V₂

Process

1.- Convert volume 1 to liters

               1000 ml ---------------------  1 l

                 200 ml ---------------------  x

                 x = (200 x 1) / 1000

                 x = 200 / 1000

                 x = 0.20 l

2.- Substitute the values in the formula

                 C₂ = (0.778 x 0.20) / 1

3.- Simplification and result

                  C₂ = 0.156 M

Answer 2

Answer:

Molarity= 0.15

Explanation:

V1= 200mL = 0.2L

M1= 0.778 M

We need to find the moles first.

According to the formula of Molarity:

Molarity = number of moles (n)/volume of solution (V)

M= n/V

n=M1 x V1

n= 0.15 moles

Now the volume is changed to V2= 1 L

However number of moles remain same.

Thus:

M2= n/V2

M2= 0.15/1

M2 = 0.15 M