Question

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Chapter 2 Review
Circle the letter of the best answer to each question below.

1. Which of the following is not a common sign that a chemical change has occurred
a. A substance changes in color
b. an odor is produced
c. A substance changes states from solid to liquid. d. Light is produced.

2. Respiration is a form of oxidation that
a. occurs in cells.
b. produces fire.
c. causes rust.
d. creates oxygen.

3. Water molecules inside a vacuum will
a. become densely packed together.
b. expand and spread evenly throughout the space.
c. form ice because there's no heat energy in a vacuum.
d. be drawn to the bottom of the container because of gravity.

4. Which of the following subatomic particles have the least amount of mass?
a. quarks
b. protons
c. neutrinos
d. electrons​

Answer 1

1 - c. A substance changing states from solid to liquid is a common sign of a physical change, not a chemical change.

2 - a. Respiration is a chemical reaction that occurs in cells, involving the oxidation of glucose to produce energy.

3 - b. Water molecules in a vacuum will expand and spread evenly throughout the space due to the absence of external forces like gravity or pressure.

4 - d. Electrons have the least amount of mass among the listed subatomic particles.