Q: Which of the following equations correctly represents the process of photosynthesis?

$$6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{sunlight} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6 \text{O}_2$$

Question 1

Which of the following best explains why sodium (Na) and chlorine (Cl) combine to form sodium chloride (NaCl) with properties very different from the original elements?

Accepted Answer

Na and Cl form an ionic bond, resulting in a compound with emergent properties.

Question 2

A sunflower field is used to clean up soil contaminated with lead and zinc. This process is known as:

Accepted Answer

Phytoremediation

Question 3

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 4

Given a sodium atom with atomic number 11 and mass number 23, how many neutrons does it have? Use the formula $$	ext{Number of neutrons} = 	ext{Mass number} - 	ext{Atomic number}.$$

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 5

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

Accepted Answer

Surface tension due to cohesion among water molecules

Question 6

Why does ice float on liquid water?

Accepted Answer

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

Question 7

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 8

Which element is required in trace amounts for normal thyroid function, and what condition can result from its deficiency?

Accepted Answer

Iodine; goiter

Question 9

A radioactive isotope is used in a PET scan to detect cancerous tissue. What property of radioactive isotopes makes this possible?

Accepted Answer

They spontaneously decay, emitting particles and energy that can be detected.

Question 10

Which of the following best explains why water is an excellent solvent for ionic and polar substances?

Accepted Answer

Water molecules are polar, allowing them to surround and separate ions and polar molecules.

Question 11

Which of the following equations correctly represents the process of photosynthesis?

Accepted Answer

$$6 	ext{CO}_2 + 6 	ext{H}_2	ext{O} + 	ext{sunlight} ightarrow 	ext{C}_6	ext{H}_{12}	ext{O}_6 + 6 	ext{O}_2$$

Question 12

Which of the following best describes the difference between cohesion and adhesion in water?

Accepted Answer

Cohesion is the attraction between water molecules; adhesion is the attraction between water and other substances.

Question 13

A solution has a pH of 5. Which of the following statements is true?

Accepted Answer

The solution is acidic and has a high concentration of H$$^+$$ ions.

Question 14

Which of the following best explains why buffers are important in biological systems?

Accepted Answer

Buffers minimize changes in pH by accepting or donating H$$^+$$ ions.

Question 15

Which of the following is a real-life application of van der Waals interactions?

Accepted Answer

The ability of geckos to walk on walls due to numerous weak interactions between their feet and surfaces.

Question 16

Which of the following best describes the relationship between atomic number, mass number, and the number of neutrons in an atom?

Accepted Answer

$$	ext{Mass number} = 	ext{Atomic number} + 	ext{Number of neutrons}$$

Question 17

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

Accepted Answer

Oxygen

Question 18

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

Accepted Answer

Oil molecules are nonpolar and do not interact with polar water molecules.

Question 19

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

Accepted Answer

Electrons can only exist at specific energy levels, and absorb or release energy to move between them.

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards