The method used in this experiment is difficult to apply for determining the formula weight of unknown salts in aqueous solutions. Even when accurate freezing point depressions are measured, the results are not always conclusive because there can be an undetermined parameter. Considering the information in the Introduction section, what is the best explanation for this difficulty?

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.