Question 1

Which of the following statements best describes an element?

Accepted Answer

An element is a substance that cannot be broken down to other substances by chemical reactions.

Question 2

Which four elements make up approximately 96% of living matter?

Accepted Answer

Carbon, hydrogen, oxygen, and nitrogen

Question 3

What is the atomic number of an element?

Accepted Answer

The number of protons in its nucleus

Question 4

Which of the following best explains why isotopes of an element behave similarly in chemical reactions?

Accepted Answer

They have the same number of protons and electrons.

Question 5

A radioactive isotope of carbon, $$^{14}C$$, is used in medical imaging. If carbon has an atomic number of 6, how many neutrons does $$^{14}C$$ have?

Accepted Answer

$$8$$

Question 6

Which statement about electron shells and energy levels is correct?

Accepted Answer

Electrons in shells farther from the nucleus have higher potential energy.

Question 7

What determines the chemical behavior of an atom?

Accepted Answer

The distribution of electrons in the electron shells, especially the valence shell

Question 8

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of a pair of valence electrons between two atoms

Question 9

In a water molecule, the oxygen atom is more electronegative than the hydrogen atoms. What type of bond is formed between the oxygen and hydrogen atoms?

Accepted Answer

Polar covalent bond

Question 10

Which of the following is true about ionic bonds?

Accepted Answer

They result from the attraction between oppositely charged ions.

Question 11

Which of the following interactions is responsible for the ability of a gecko to climb smooth walls?

Accepted Answer

Van der Waals interactions

Question 12

Why are weak chemical interactions, such as hydrogen bonds, important in biological systems?

Accepted Answer

They allow for the reversible interactions necessary for biological processes.

Question 13

Which of the following best explains why molecular shape is crucial in biology?

Accepted Answer

Molecular shape determines how molecules recognize and respond to each other.

Question 14

Which of the following is an example of a chemical reaction?

Accepted Answer

Photosynthesis: $$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 15

What does it mean when a chemical reaction has reached equilibrium?

Accepted Answer

The forward and reverse reactions occur at the same rate.

Question 16

Which of the following best describes a trace element?

Accepted Answer

An element required by an organism in minute quantities

Question 17

If an atom has 7 protons, 8 neutrons, and 7 electrons, what is its atomic mass?

Accepted Answer

$$15$$

Question 18

Which of the following is true about valence electrons?

Accepted Answer

They determine the chemical behavior of an atom.

Question 19

Which of the following best describes a hydrogen bond?

Accepted Answer

A bond between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom

Question 20

Which of the following is NOT a property of compounds?

Accepted Answer

They always have the same properties as their elements.

Chapter 2: The Chemical Context of Life – Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드