$$\text{Atomic mass} = \text{Number of protons} + \text{Number of neutrons}$$

Question 1

Which of the following best describes a pheromone as discussed in the context of rattlebox moths?

Accepted Answer

A chemical released outside the body to stimulate behavioral responses in other individuals of the same species.

Question 2

Which four elements make up approximately 96% of the human body by weight?

Accepted Answer

Carbon, hydrogen, oxygen, and nitrogen

Question 3

What is the definition of an element in chemistry?

Accepted Answer

A substance that cannot be broken down into other substances by ordinary chemical means.

Question 4

Which of the following is a trace element that is essential for preventing goiter?

Accepted Answer

Iodine

Question 5

Given the atomic structure, what is the atomic mass of an atom with 8 protons and 8 neutrons?

Accepted Answer

$$16$$

Question 6

Which statement about isotopes is correct?

Accepted Answer

Isotopes of an element have the same atomic number but different atomic masses.

Question 7

What is the atomic number of a neutral atom with 12 protons, 12 neutrons, and 12 electrons?

Accepted Answer

$$12$$

Question 8

Which of the following best explains why radioactive isotopes can be used as tracers in biological research?

Accepted Answer

Radioactive isotopes behave chemically the same as nonradioactive isotopes, allowing them to be tracked in living systems.

Question 9

Which compound is formed by the combination of sodium and chlorine in a 1:1 ratio?

Accepted Answer

NaCl (Sodium chloride)

Question 10

A patient is diagnosed with anemia. Which trace element deficiency is most likely responsible?

Accepted Answer

Iron

Question 11

Which of the following is true about the mass of subatomic particles?

Accepted Answer

The mass of an electron is negligible compared to a proton.

Question 12

Which scenario best illustrates the danger of long-term exposure to high-energy radiation?

Accepted Answer

A person develops lung cancer after radon contamination in their house.

Question 13

Which equation correctly represents the calculation of atomic mass?

Accepted Answer

$$	ext{Atomic mass} = 	ext{Number of protons} + 	ext{Number of neutrons}$$

Question 14

Which of the following is a correct statement about compounds?

Accepted Answer

Compounds contain two or more elements in a fixed ratio.

Question 15

A molecule of water is represented by which chemical formula?

Accepted Answer

$$H_2O$$

Question 16

Which of the following is NOT a role of chemicals in living organisms?

Accepted Answer

Regulating the Earth's orbit

Question 17

Which of the following statements about radioactive isotopes is correct?

Accepted Answer

Radioactive isotopes have unstable nuclei that decay spontaneously, emitting particles and energy.

Question 18

Why are trace elements added to food and water?

Accepted Answer

To prevent dietary deficiencies that can cause physiological conditions.

Question 19

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

Accepted Answer

A molecule can be made of the same or different elements, while a compound is always made of different elements.

Question 20

A botanist uses $$CO_2$$ containing $$^{14}C to $$trace photosynthesis in plants. What property of $$^{14}C$$ makes this possible?

Accepted Answer

It is radioactive and can be detected as it decays.

Chapter 2: The Chemical Basis of Life – Study Notes

Study Guide - Practice Questions