Question

What volume of 0.025 M sodium bromide solution, NaBr (aq), contains 2.0 x 10^¯4 moles of (bar)Br? Show your workings in dimensional analysis.

A. 0.080 dm³
B. 4.0 cm³
C. 8.0 cm³
D. 16.0 cm³

Answer 1

To find the volume of 0.025 M sodium bromide solution containing 2.0 x 10^-4 moles of Br-, the molarity formula M = n/V was used. After calculation, the volume is found to be 8.0 cm³.OPTION(C).

Step-by-step explanation:

To find the volume of 0.025 M sodium bromide (NaBr) solution that contains 2.0 x 10­4 moles of Br­, we can use the concept of molarity, which is defined as moles of solute per liter of solution (mol/L). Given the molarity (M) and the moles of solute (n), we can calculate volume (V) using the formula:

M = n/V

Now, rearrange the formula to solve for V:

V = n/M

Substituting the given values:

V = (2.0 x 10­4 mol)/(0.025 mol/L)

V = 0.008 L

To convert liters (L) to cubic decimeters (dm³), since 1 L = 1 dm³, we do not need to convert it:

V = 0.008 dm³

To convert cubic decimeters to cubic centimeters (cm³), knowing that 1 dm³ = 1000 cm³, we multiply by 1000:

V = 0.008 dm³ x 1000 cm³/dm³

V = 8.0 cm³

Therefore, the correct answer is 8.0 cm³.