Question 1

Which of the following statements best explains why sodium chloride (NaCl) has properties different from those of its constituent elements, sodium and chlorine?

Accepted Answer

NaCl is a compound, and compounds have emergent properties that differ from the elements that form them.

Question 2

A radioactive isotope of carbon, $$^{14}C$$, is used in radiometric dating. If the half-life of $$^{14}C is 5$$,730 years, how much of a 100 g sample would remain after 11,460 years?

Accepted Answer

$$25\ \mathrm{g}$$

Question 3

Which of the following best describes the difference between a covalent bond and an ionic bond?

Accepted Answer

A covalent bond involves the sharing of electrons, while an ionic bond involves the transfer of electrons.

Question 4

Which element is most abundant in the human body by mass?

Accepted Answer

Oxygen

Question 5

A patient is given a radioactive tracer to monitor cancer metabolism. Which property of radioactive isotopes makes this possible?

Accepted Answer

They emit detectable particles and energy as they decay.

Question 6

Which of the following best explains why noble gases such as helium and neon are chemically inert?

Accepted Answer

They have full valence electron shells.

Question 7

If an atom has an atomic number of 7 and a mass number of 15, how many neutrons does it have?

Accepted Answer

$$8$$

Question 8

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally between atoms, resulting in partial charges.

Question 9

A gecko can climb smooth surfaces due to which type of weak chemical interaction?

Accepted Answer

Van der Waals interactions

Question 10

Which of the following is true about chemical reactions?

Accepted Answer

They involve the making and breaking of chemical bonds.

Question 11

Which statement best explains why water (H$$_2O) is a $$polar molecule?

Accepted Answer

Oxygen is more electronegative than hydrogen, causing unequal sharing of electrons.

Question 12

Which of the following best describes the role of trace elements in the human body?

Accepted Answer

They are required in minute quantities for proper physiological function.

Question 13

A molecule of methane (CH$$_4) $$has which type of covalent bonds between carbon and hydrogen?

Accepted Answer

Single covalent bonds

Question 14

Which of the following best explains why the shape of a molecule is important in biology?

Accepted Answer

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

Question 15

Which of the following is an example of a chemical reaction that is essential for life and is reversible?

Accepted Answer

$$3H_2 + N_2$ \rightleftharpoons 2NH_3$$

Question 16

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 17

Which of the following is a correct statement about valence electrons?

Accepted Answer

They are found in the outermost electron shell and determine chemical behavior.

Question 18

A scientist finds a fossil and measures the ratio of parent to daughter isotopes. If the half-life of the parent isotope is 1 million years and the ratio is 1:3 (parent:daughter), how old is the fossil?

Accepted Answer

$$2\ 	ext{million years}$$

Question 19

Which of the following best explains why ionic compounds like NaCl dissociate easily in water?

Accepted Answer

Water molecules surround and separate the ions due to their polarity.

Question 20

Which of the following is a real-world application of the concept of electronegativity?

Accepted Answer

The polarity of water molecules allows them to dissolve many substances, making water an excellent solvent.

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards