Type the correct answer in the box.

A pharmacist works with a 1.75 M solution of sodium bromide (NaBr) and water. The volume of the solution is 84.0 milliliters. If the pharmacist dilutes the solution to 1.00 M, what is the volume of the new solution?

Express your answer to three significant figures.

The volume of the new solution is ______ milliliters.



Answer :

To find the volume of the new solution when the concentration is changed, we need to follow these steps:

1. Determine the number of moles of solute present in the initial solution:
- The concentration (C) of the initial solution is 1.75 M (moles per liter).
- The volume (V) of the initial solution is 84.0 milliliters (which is 0.084 liters as 1 liter = 1000 milliliters).

The formula to calculate moles (n) is:
[tex]\[ n = C \times V \][/tex]

Plugging in the initial values:
[tex]\[ n = 1.75 \, \text{M} \times 0.084 \, \text{L} = 0.147 \, \text{moles} \][/tex]

So, the initial solution contains 0.147 moles of sodium bromide (NaBr).

2. Calculate the new volume of the solution which has the same moles but a different concentration:
- The final concentration (C') is 1.00 M.
- The number of moles of solute remains the same at 0.147 moles.

The formula to find the volume of a solution given its concentration and the number of moles is:
[tex]\[ V' = \frac{n}{C'} \][/tex]

Plugging in the values:
[tex]\[ V' = \frac{0.147 \, \text{moles}}{1.00 \, \text{M}} = 0.147 \, \text{L} \][/tex]

Converting this volume back to milliliters:
[tex]\[ 0.147 \, \text{L} \times 1000 \, \text{mL/L} = 147.0 \, \text{mL} \][/tex]

Thus, the volume of the new solution is 147.0 milliliters.