Answers
1. Homogenous differs from heterogenous as C. it is uniform in appearance. It means that its components are not visible to the eye.
2. To check if a liquid sample is a substance or a mixture, the best test to use is/are C. III and IV only. There are homogenous mixtures that can be mistaken as substances so color is not the best test to use. Tasting is not a good test either.
3. At sea level, an odorless and colorless material that boils at 100⁰C and freeze at 0⁰C means that D. The material is a pure substance. Water is a pure substance and boils at 100⁰C and freeze at 0⁰C.
4. The piece of the aluminum foil that Jill took compared with the rest that was left in the box means that A. Its mass and melting point are different. Melting point can be affected by the quantity of the sample.
5. The samples that are the same substance are A. Liquid A and B. The boiling point of a substance doesn't depend on its volume but for its temperature and pressure. Liquid A and B are the same substance because they have the same boiling point.
6. Matter is classified into C. Substance and Mixture. Substance is divided into element and compound while Mixture is divided into homogenous and heterogeneous mixtures.
7. B. Substance is pure while mixture is impure is true. Substance is only made of one matter and its components cannot be separated.
8. The statement C. Water is a mixture of Oxygen and Nitrogen is not true. Water is not a mixture and doesn't contain nitrogen.
9. The process used to separate salt from water in seawater is B. Evaporation. Seawater is a solution of many different solids in water so filtration and decantation will not work. Scooping is not possible.
