Question

1. which of the following would be classified as a heterogeneous mixture?

a. vinegar c. salt water
b. oil and water d. isopropyl alcohol

1. ___ should be used to separate sand from water.

a. distillation
b. chromatography
c. filtration

1. which type of matter would not be classified as a pure substance?

a. milk
b. sodium chloride
c. nitrogen
d. calcium hydroxide

Explanation:

1. A heterogeneous mixture has distinct, non-uniform components. Oil and water form separate layers, so it is heterogeneous. Vinegar, salt water, and isopropyl alcohol are homogeneous mixtures.
2. Filtration separates solid particles (sand) from a liquid (water) using a filter that traps solids while letting liquid pass. Distillation separates by boiling points, chromatography by component movement, which are not suitable here.
3. Pure substances are elements or compounds with fixed composition. Milk is a mixture of fats, proteins, water, etc., so it is not a pure substance. Sodium chloride, nitrogen, and calcium hydroxide are pure substances (compound, element, compound respectively).

Answer:

1. B. oil and water
2. C. filtration
3. A. milk