Question 1

Why is lemon often added to seafood, such as shrimp, before eating?

Accepted Answer

Lemon contains citric acid, which reacts with amines in seafood to reduce the fishy odor.

Question 2

Which of the following best describes a chemical change?

Accepted Answer

A process in which one or more substances are converted into different substances with new chemical properties.

Question 3

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

Salt and pepper mixed together

Question 4

What is the correct electron-dot (Lewis) structure for an oxygen molecule ($$\mathrm{O}_2$$)?

Accepted Answer

$$\cdot\cdot\mathrm{O}=\mathrm{O}\cdot\cdot$$

Question 5

Which process is endothermic?

Accepted Answer

Melting of ice

Question 6

Which statement about atoms and molecules is correct?

Accepted Answer

Molecules are formed when two or more atoms chemically bond together.

Question 7

Which of the following is a pure substance?

Accepted Answer

Aluminum foil (Al)

Question 8

Which of the following best describes the difference between a compound and a mixture?

Accepted Answer

A compound consists of two or more elements chemically bonded, while a mixture contains substances physically combined.

Question 9

Which of the following is an example of a physical change?

Accepted Answer

Evaporation of water

Question 10

Which statement about exothermic reactions is true?

Accepted Answer

Exothermic reactions release heat to the surroundings.

Question 11

Which of the following is the correct symbol, atomic number, and mass number for Argon?

Accepted Answer

Symbol: Ar, Atomic number: 18, Mass number: 40

Question 12

Which of the following best explains why platinum is used in the treatment of cancer?

Accepted Answer

Platinum compounds can interfere with DNA replication in cancer cells.

Question 13

Which of the following is a correct flow-chart classification for seawater?

Accepted Answer

Mixture $$\rightarrow$$ Homogeneous mixture

Question 14

Which of the following processes is used to separate a mixture of salt and pepper?

Accepted Answer

Manual separation based on physical properties

Question 15

Which of the following is NOT a fundamental particle of matter?

Accepted Answer

Molecule

Question 16

Which of the following statements about energy is correct?

Accepted Answer

Energy is the capacity to do work or produce heat.

Question 17

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Salt dissolved in water

Question 18

Which of the following best describes the process of photosynthesis?

Accepted Answer

Conversion of light energy into chemical energy by plants.

Question 19

Which of the following is a correct example of a chemical change?

Accepted Answer

Burning gasoline in a car engine

Question 20

Which of the following is the correct flow-chart classification for calcium carbonate ($$\mathrm{CaCO}_3$$)?

Accepted Answer

Pure substance $$\rightarrow$$ Compound

Foundations and Classification in General Chemistry: Matter, Changes, and Flowcharts

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