Chemistry Unit Test

Please write your full name below.

1. Based on the model, what is the chemical formula of butane?

• A. C3H8
• B. C3H10
• C. C4H10
• D. C3H12

2. What is the correct classification for carbon dioxide (CO₂)?

• A. element
• B. compound
• C. mixture
• D. Both B and C

3. A compound is

• A. A substance made up of two or more atoms joined by chemical bonds.
• B. Two substances not chemically combined.
• C. A substance that cannot be separated even by a chemical reaction.
• D. Two substances that can be joined together by physical means.

4. A molecule is

• A. the smallest particle of an atom
• B. has no charge and lives in the nucleus.
• C. a subatomic particle with a negative charge.
• D. the smallest unit of a compound

5. Which of the following is an example of a molecule?

• A. Gold (Au)
• B. Chlorine (Cl₂)
• C. Water (H₂O)
• D. Both B and C

6. All of the following describe a physical property EXCEPT?

• A. color
• B. density
• C. reactivity
• D. solubility

7. Which of the following is NOT a characteristic of a compound?

• A. has different properties from the elements that formed it
• B. pure substance made of two or more elements
• C. the smallest unit of a compound is an atom
• D. can be represented by a chemical formula

8. Which of the following statements is true about a physical property?

• A. It can only be observed during a chemical reaction.
• B. It describes the ability of a substance to undergo a chemical change.
• C. It can be observed without changing the chemical composition of a substance.
• D. It is always related to the substance's ability to burn.

9. In a reaction lithium sulfide is produced by combining lithium with sulfur. The mass of lithium is 12.3 g and the mass of sulfur is 10.1 g. What is the mass for the lithium sulfide that is produced?

• A. 22 g
• B. 32.4 g
• C. 22.4 g
• D. 10.1 g