Question 1

Which of the following statements best describes a compound?

Accepted Answer

A compound is a substance consisting of two or more elements in a fixed ratio, with characteristics different from its constituent elements.

Question 2

Which four elements make up approximately 96% of the human body’s mass?

Accepted Answer

Oxygen, Carbon, Hydrogen, Nitrogen

Question 3

An atom of carbon-14 has how many neutrons?

Accepted Answer

8

Question 4

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic bond?

Accepted Answer

Sodium donates an electron to chlorine, resulting in oppositely charged ions that attract each other.

Question 5

Which of the following is true about isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 6

Which type of chemical bond is formed when two atoms share a pair of electrons unequally?

Accepted Answer

Polar covalent bond

Question 7

What is the main reason that elements with a full valence shell are chemically inert?

Accepted Answer

Their outermost electron shell is stable and does not need to gain or lose electrons.

Question 8

Which of the following best describes a hydrogen bond?

Accepted Answer

A hydrogen bond is a weak attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Question 9

Which equation correctly represents the balanced chemical reaction for photosynthesis?

Accepted Answer

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

Question 10

Which of the following statements about van der Waals interactions is correct?

Accepted Answer

They occur when electrons are distributed asymmetrically, causing temporary charges that attract molecules close together.

Question 11

A molecule’s shape is crucial for its biological function because:

Accepted Answer

It allows molecules to recognize and bind to specific receptors.

Question 12

Which of the following best explains why morphine and endorphins can bind to the same brain receptors?

Accepted Answer

They have similar molecular shapes, allowing them to fit into the same receptor sites.

Question 13

If an atom has an atomic number of 11 and a mass number of 23, how many neutrons does it have?

Accepted Answer

12

Question 14

Which of the following is a trace element in the human body?

Accepted Answer

Iron

Question 15

Which of the following best describes potential energy in the context of electrons in an atom?

Accepted Answer

Potential energy is the energy electrons have due to their location in electron shells.

Question 16

Which of the following is NOT a subatomic particle found in atoms?

Accepted Answer

Ion

Question 17

Which of the following statements about chemical reactions is correct?

Accepted Answer

Chemical reactions involve the making or breaking of chemical bonds, rearranging atoms.

Question 18

Which of the following best describes an ion?

Accepted Answer

An ion is an atom or molecule with a net electrical charge due to the loss or gain of electrons.

Question 19

Which of the following elements is most likely to be chemically inert?

Accepted Answer

Neon (Ne)

Question 20

Which of the following is the correct definition of electronegativity?

Accepted Answer

Electronegativity is the ability of an atom to attract electrons in a covalent bond.

The Chemistry of Life: Elements, Compounds, and Atomic Structure

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