Question 1

Which statement best explains the concept of 'emergent properties' as it applies to compounds such as sodium chloride (NaCl)?

Accepted Answer

Emergent properties are new characteristics that arise when elements combine to form compounds, which are different from the properties of the individual elements.

Question 2

A neutral atom of sodium has an atomic number of 11 and a mass number of 23. How many neutrons does it contain?

Accepted Answer

$$12$$

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 between atoms, while an ionic bond involves the transfer of electrons from one atom to another.

Question 4

Which of the following elements is considered a trace element essential for vertebrate health, and what is a consequence of its deficiency?

Accepted Answer

Iodine; goiter

Question 5

Radioactive isotopes are useful in biological research for all of the following EXCEPT:

Accepted Answer

Increasing the stability of cellular molecules

Question 6

Which equation correctly represents the relationship between pH and hydrogen ion concentration $$[H^+]$$?

Accepted Answer

$$pH = -\log[H^+]$$

Question 7

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-4}$$ M. What is its pH?

Accepted Answer

$$4$$

Question 8

Which property of water allows it to moderate temperature changes in organisms and environments?

Accepted Answer

High specific heat

Question 9

Why does ice float on liquid water?

Accepted Answer

Hydrogen bonds in ice are more 'ordered,' making ice less dense than liquid water.

Question 10

Which of the following best describes a buffer in biological systems?

Accepted Answer

A buffer is a substance that minimizes changes in the concentrations of $$H^+$$ and $$OH^- in a $$solution.

Question 11

Which of the following is a consequence of ocean acidification caused by increased atmospheric $$CO_2$$?

Accepted Answer

Decrease in carbonate ion concentration, threatening organisms that build shells and coral reefs

Question 12

Which of the following best explains why water is an effective solvent for ionic compounds?

Accepted Answer

Water molecules are polar and form hydration shells around ions, separating them.

Question 13

A scientist dissolves $$58.44 g of $$NaCl (molecular mass $$= 58.44 g/$$mol) in $$1 L of $$water. What is the molarity of the solution?

Accepted Answer

$$1 M$$

Question 14

Which of the following best describes the role of hydrogen bonds in the properties of water?

Accepted Answer

Hydrogen bonds allow water to have a high specific heat, surface tension, and cohesive behavior.

Question 15

Which of the following chemical reactions is an example of a reversible reaction in biological systems?

Accepted Answer

$$H_2CO_3 \rightleftharpoons $$HCO_3$$^- + H^+$$

Question 16

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation is a positively charged ion, while an anion is negatively charged.

Question 17

Which of the following is true about the movement of electrons between energy levels in an atom?

Accepted Answer

Electrons move to higher energy levels by absorbing energy.

Question 18

Which of the following best explains why van der Waals interactions can be significant in biological systems?

Accepted Answer

They are weak interactions that, when numerous, can collectively stabilize large biological molecules.

Question 19

Which of the following is a real-world application of the ability of certain plants to tolerate toxic elements?

Accepted Answer

Sunflower plants are used to detoxify soils contaminated with heavy metals after environmental disasters.

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards