Question 1

Which subatomic particle is responsible for the chemical properties of an element, and where is it located in the atom?

Accepted Answer

Electron; orbiting the nucleus

Question 2

Given the atomic number and mass number for carbon ($$^{12}_{6}C$$), how many neutrons does a typical carbon atom have?

Accepted Answer

$$6$$ neutrons

Question 3

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Hydrogen bonds in ice force water molecules farther apart, decreasing density

Question 4

Which of the following equations correctly represents the dissociation of water?

Accepted Answer

$$\mathrm{H_2O} \rightarrow \mathrm{H^+} + \mathrm{OH^-}$$

Question 5

A sodium atom (Na) loses one electron to become a sodium ion (Na$$^+). $$What is the resulting charge and why?

Accepted Answer

Positive, because it loses an electron

Question 6

Which property of water allows insects to walk on its surface, as shown in the image?

Accepted Answer

Cohesion and surface tension

Question 7

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is two or more atoms joined together; a compound is two or more different elements joined together

Question 8

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons

Question 9

Which type of chemical bond is the strongest and most common in living organisms?

Accepted Answer

Covalent bond

Question 10

What is the main reason water is an excellent solvent for ionic and polar substances?

Accepted Answer

Water is polar and forms hydrogen bonds with solutes

Question 11

If the pH of a solution changes from 6 to 4, how does the hydrogen ion concentration change?

Accepted Answer

It increases by a factor of 100

Question 12

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

Accepted Answer

Buffers resist changes in pH by absorbing excess H$$^+ or OH$^-$$ ions

Question 13

Which of the following is a correct representation of the carbonic acid buffer system in the human body?

Accepted Answer

$$\mathrm{CO_2$} + \mathrm{H_2O} \leftrightarrow \mathrm{H_2CO_3} \leftrightarrow \mathrm{$$HCO_3$$^-} + \mathrm{H^+}$$

Question 14

Which of the following best explains why sodium chloride (NaCl) dissolves in water?

Accepted Answer

Water molecules form spheres of hydration around Na$$^+$$ and Cl$$^-$$ ions

Question 15

Which of the following is true about isotopes?

Accepted Answer

Isotopes have the same number of protons but different numbers of neutrons

Question 16

Which of the following best describes a polar covalent bond?

Accepted Answer

Electrons are shared unequally, creating partial charges

Question 17

Which of the following is a real-life application of radioisotopes in medicine?

Accepted Answer

Radioisotopes are used to sterilize surgical equipment

Question 18

Which of the following best explains why water has a high heat capacity?

Accepted Answer

Hydrogen bonds between water molecules absorb a lot of energy before breaking

Question 19

Which of the following is true about van der Waals interactions?

Accepted Answer

They are weak, temporary attractions between molecules due to partial charges

Chemistry of Life: Foundations for Microbiology

Study Guide - Practice Questions