Question

a biochemist carefully measures the molarity of ammonium chloride in 31. ml of photobacterium cell growth medium to be 2.5 μm. unfortunately, a careless graduate student forgets to cover the container of growth medium and a substantial amount of the solvent evaporates. the volume of the cell growth medium falls to 8.9 ml. calculate the new molarity of ammonium chloride in the photobacterium cell growth medium. be sure your answer has the correct number of significant digits.

Explanation:

Step1: Use the dilution formula

The dilution formula is \(C_1V_1 = C_2V_2\), where \(C_1\) is the initial concentration, \(V_1\) is the initial volume, \(C_2\) is the final concentration, and \(V_2\) is the final volume.
Given \(C_1 = 2.5\ \mu M\), \(V_1=31\ mL\), and \(V_2 = 8.9\ mL\).
We need to solve for \(C_2\), so \(C_2=\frac{C_1V_1}{V_2}\).

Step2: Substitute the values

Substitute the values into the formula: \(C_2=\frac{2.5\ \mu M\times31\ mL}{8.9\ mL}\).
First, calculate \(2.5\times31 = 77.5\).
Then, \(\frac{77.5}{8.9}\approx8.7\).

Answer:

\(8.7\ \mu M\)