Question 1

Which of the following best describes an isotope of an element?

Accepted Answer

An atom with the same number of protons but a different number of neutrons.

Question 2

Which of the following statements about covalent bonds is correct?

Accepted Answer

A covalent bond involves the sharing of electron pairs between atoms.

Question 3

A molecule of water ($$\mathrm{H_2O}) is $$considered polar because:

Accepted Answer

The oxygen atom is more electronegative than the hydrogen atoms, creating a partial negative charge near the oxygen.

Question 4

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

Accepted Answer

Hydrogen bonds in ice create a lattice that is less dense than liquid water.

Question 5

Which of the following is the correct molecular formula for glucose, a common macromolecule monomer?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$}$$

Question 6

Which of the following best describes a hydrogen bond?

Accepted Answer

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

Question 7

If an atom has an atomic number of 17 and a mass number of 35, how many neutrons does it have?

Accepted Answer

$$35 - 17 = 18$$ neutrons

Question 8

Which of the following best describes the difference between an ion and an atom?

Accepted Answer

An ion has a different number of electrons than protons, giving it a net charge.

Question 9

Which of the following is a property of water that results from hydrogen bonding and is critical for life?

Accepted Answer

High heat of vaporization

Question 10

A solution has a pH of 4. What is the hydrogen ion concentration $$[\mathrm{H^+}] in $$moles per liter?

Accepted Answer

$$[\mathrm{H^+}] = 10$$^{-4}$$ \ \mathrm{mol/L}$$

Question 11

Which of the following best explains why sodium chloride ($$\mathrm{NaCl}) $$dissolves easily in water?

Accepted Answer

Water molecules surround the ions, stabilizing them through ion-dipole interactions.

Question 12

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

Accepted Answer

Valence electrons are found in the outermost shell and determine an atom's chemical reactivity.

Question 13

Which of the following best describes the difference between polar and nonpolar covalent bonds?

Accepted Answer

Polar covalent bonds involve unequal sharing of electrons, while nonpolar covalent bonds involve equal sharing.

Question 14

A patient is given an intravenous solution of 0.9% NaCl. This solution is considered:

Accepted Answer

An electrolyte, because it dissociates into ions in water.

Question 15

Which of the following best describes the concept of 'partial charges' in a water molecule?

Accepted Answer

Oxygen has a partial negative charge and hydrogens have partial positive charges due to unequal electron sharing.

Question 16

Which of the following is an example of adhesion in biological systems?

Accepted Answer

Water molecules sticking to the walls of plant xylem vessels.

Question 17

Which of the following best explains why oil does not dissolve in water?

Accepted Answer

Oil is nonpolar and cannot form hydrogen bonds with water.

Question 18

Which of the following is the correct order of filling for electron shells in an atom?

Accepted Answer

First shell, then second shell, then third shell

Question 19

A solution is made by dissolving 10 grams of glucose in 100 mL of water. In this solution, glucose is the:

Accepted Answer

Solute

Question 20

Which of the following best describes a macromolecule?

Accepted Answer

A large molecule composed of many smaller subunits called monomers.

Question 21

Which of the following properties of water is most important for temperature regulation in living organisms?

Accepted Answer

High specific heat capacity

Chapter 2: The Chemical Context of Life – Study Notes

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