II. Multiple Choice. Choose the letter of the correct answer and write it in the space provided before the number.
1. Mixtures can be separated by physical methods while pure substances cannot. Which of the following groups contain only pure substances?
A. air, methane, sodium chloride
B. iron, ethanol, calcium fluoride
C. ammonia, vinegar, and silicon
D. carbon dioxide, air, water
2. Which of the following lists of materials are composed of mixtures?
A. vinegar, 70% alcohol, carbon
B. oxygen, sodium chloride, water
C. blood, calamansi juice, air
D. carbon dioxide, bleach, oil
3. In the lab, Kane is using a substance that has a chemical formula and contains two different elements. What is Kane's substance?
A. element
B. heterogeneous mixture
C. compound
D. homogeneous mixture
4. Oliver heated a liquid in a casserole. He forgot to turn off the stove right away and all the liquid was gone. But he noticed that there were some solid materials that settled at the surface of the casserole. What can be inferred from this observation?
A. The liquid was a pure substance.
B. The liquid was a mixture with dissolved solid materials.
C. The liquid was composed of a single material.
D. The liquid material was a pure substance because it evaporated.
5. How do compounds differ from elements?
A. A compound is a combination of two or more elements.
B. A compound cannot be broken down into parts.
C. A compound is made up of the same type of atoms.
D. A compound is a pure substance, elements are not.