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 plant 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

Calculate the number of neutrons in a sodium atom with a mass number of 23 and an atomic number of 11. 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

Question 6

Why does ice float on liquid water?

Accepted Answer

Hydrogen bonds in ice are more ordered, making ice 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 interact with charged and polar solutes.

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 geckos can walk on walls?

Accepted Answer

Geckos use numerous van der Waals interactions between tiny hairs on their feet and the wall surface.

Question 15

Which of the following is a function of buffers in biological systems?

Accepted Answer

Buffers minimize changes in the concentrations of H$$^+$$ and OH$$^-$$ ions.

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; an anion is a negatively charged ion.

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 water has a high specific heat?

Accepted Answer

Hydrogen bonds between water molecules absorb heat when they break and release heat when they form.

Question 19

Which of the following is true about the atomic structure of an element?

Accepted Answer

The atomic number is the number of protons in the nucleus.

Chapter 2: The Chemical Context of Life – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards