Question

1. Using the structural formulas for ammonia (NH3 on the left) and hexane (C6H14 on the right) below which statement explains what will happen when ammonia and hexane are mixed?

A. Hexane will dissolve with ammonia if you stir them together for 10 minutes

B. Ammonia and hexane will not dissolve because one molecule is polar and the other is non polar.

C. Ammonia and hexane will dissolve together

D. Ammonia and hexane will not dissolve because one molecule is ionic and the other is non polar


2. If you add water to 750.0 mL of a 2.800 M KCl solution, and its molarity changes to 1.500 M, what will the new volume be?


1200 mL

401.0 mL

1400 mL

800.0 mL

Answer 1

1. B. Ammonia and hexane will not dissolve because one molecule is polar and the other is non polar.

2. 1400 mL

Step-by-step explanation:

In chemistry, like dissolve like! Ammonia is a polar molecule having a significant dipole moment owing to its three N-H bonds. On the other hand, hexane is a purely non-polar hydrocarbon hence the two substances can never dissolve in each other.

From the dilution formula;

C1V1=C2V2

C1= Initial concentration of the solution

V1 = Initial volume of the solution

C2 = Final concentration of the solution

V2= Final volume of the solution

2.8 M * 750.0 mL = 1.5 M * V2

V2 = 2.8 M * 750.0 mL/1.5 M

V2 = 1400 mL