Question 1

Which of the following elements makes up the largest percentage of body mass in humans?

Accepted Answer

Oxygen

Question 2

Wood ants (Formica rufa) use formic acid as a chemical defense. What property of formic acid allows it to be effective in warding off predators?

Accepted Answer

It is a corrosive acid that irritates and deters predators.

Question 3

Which statement best describes an emergent property of sodium chloride ($$\mathrm{NaCl}) $$compared to its constituent elements?

Accepted Answer

Sodium chloride is a stable solid, unlike sodium or chlorine alone.

Question 4

Which of the following is NOT considered one of the essential elements that make up 96% of living matter?

Accepted Answer

Calcium

Question 5

Trace elements are required by organisms in minute quantities. Which of the following is a trace element?

Accepted Answer

Iron

Question 6

What determines the chemical behavior of an atom?

Accepted Answer

The distribution of electrons in the electron shells

Question 7

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons are found in the outermost shell and determine chemical reactivity.

Question 8

Which type of bond involves the sharing of one pair of valence electrons between two atoms?

Accepted Answer

Single covalent bond

Question 9

What is the main difference between a polar covalent bond and a nonpolar covalent bond?

Accepted Answer

Polar covalent bonds have unequal sharing of electrons due to differences in electronegativity.

Question 10

In the water molecule ($$\mathrm{H_2O}$$), what causes the partial charges on the hydrogen and oxygen atoms?

Accepted Answer

Oxygen is more electronegative, pulling shared electrons closer and creating a partial negative charge.

Question 11

Which of the following best describes an ionic bond?

Accepted Answer

A bond formed by the attraction between oppositely charged ions.

Question 12

Why are covalent bonds generally stronger than ionic bonds in aqueous solutions?

Accepted Answer

Water molecules disrupt ionic bonds by surrounding ions, reducing their attraction.

Question 13

Which of the following weak chemical interactions is responsible for the adhesion of a gecko's toe hairs to a wall surface?

Accepted Answer

Van der Waals interactions

Question 14

A hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom. In living cells, which atoms are most commonly involved as the electronegative partners?

Accepted Answer

Oxygen and nitrogen

Question 15

Which of the following is the correct balanced chemical equation for photosynthesis?

Accepted Answer

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

Question 16

Which of the following statements about chemical reactions is true?

Accepted Answer

Chemical reactions make and break chemical bonds, converting reactants into products.

Question 17

Which of the following molecules contains a double covalent bond?

Accepted Answer

Oxygen ($$\mathrm{O_2$})$$

Question 18

Which property of weak chemical interactions is advantageous for biological molecules?

Accepted Answer

They allow molecules to change shape and function reversibly.

Question 19

If an atom has a full valence shell, what is its chemical behavior?

Accepted Answer

It is chemically inert.

Question 20

Which of the following best explains why sodium (Na) and chlorine (Cl) form an ionic bond to create sodium chloride ($$\mathrm{NaCl}$$)?

Accepted Answer

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

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards