Question 1

Which of the following statements best explains why a compound such as sodium chloride (NaCl) has properties different from its constituent elements, sodium and chlorine?

Accepted Answer

Compounds have emergent properties that arise from the specific arrangement and bonding of their constituent elements.

Question 2

A radioactive isotope of carbon, $$^{14}\mathrm{C}$$, is used in radiometric dating. If the half-life of $$^{14}\mathrm{C} is 5$$,730 years, how much of a 100 g sample would remain after 11,460 years?

Accepted Answer

25 g

Question 3

Which of the following best describes the difference between a covalent bond and an ionic bond?

Accepted Answer

Covalent bonds involve the sharing of electrons, while ionic bonds involve the transfer of electrons.

Question 4

Which of the following elements is NOT one of the four that make up approximately 96% of living matter?

Accepted Answer

Sulfur

Question 5

A certain atom has an atomic number of 8 and a mass number of 18. How many neutrons does this atom have?

Accepted Answer

10

Question 6

Why are radioactive isotopes useful as tracers in medical diagnostics?

Accepted Answer

They emit energy that can be detected, allowing tracking of specific molecules in the body.

Question 7

Which of the following best explains why noble gases such as neon are chemically inert?

Accepted Answer

They have a full valence shell of electrons.

Question 8

A molecule of water ($$\mathrm{H}_2\mathrm{O}) is $$held together by which type of bond, and what type of bond forms between water molecules?

Accepted Answer

Covalent bonds within the molecule; hydrogen bonds between molecules

Question 9

Which of the following statements about van der Waals interactions is correct?

Accepted Answer

They are weak attractions that occur when transient local partial charges develop in molecules.

Question 10

Which scenario best illustrates the concept of chemical equilibrium?

Accepted Answer

The rate of the forward reaction equals the rate of the reverse reaction, and the concentrations of reactants and products remain constant.

Question 11

Which of the following best describes why morphine and endorphins can both bind to the same receptors in the brain?

Accepted Answer

They have similar molecular shapes, allowing them to fit into the same receptor sites.

Question 12

If an atom has 7 electrons, how many of these are valence electrons if the first shell holds 2 electrons?

Accepted Answer

5

Question 13

Which of the following is a trace element required by humans and what is its significance?

Accepted Answer

Iron; it is essential for oxygen transport in blood.

Question 14

Which of the following best describes the process of photosynthesis as a chemical reaction?

Accepted Answer

It is a process where sunlight powers the conversion of carbon dioxide and water into glucose and oxygen.

Question 15

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 16

Which of the following best explains why atoms tend to form chemical bonds?

Accepted Answer

To achieve a full valence shell and reach a more stable, lower energy state.

Question 17

A patient is injected with a radioactive tracer to monitor cancer growth using a PET scan. Which property of the tracer allows this technique to work?

Accepted Answer

The tracer emits detectable particles or energy as it decays.

Question 18

Which of the following is true regarding the formation of ions?

Accepted Answer

A cation is formed when an atom loses one or more electrons.

Question 19

Which of the following best describes the relationship between atomic number and atomic mass?

Accepted Answer

Atomic number is the number of protons; atomic mass is the sum of protons and neutrons.

Question 20

Which of the following is a real-world example of adaptation to toxic elements?

Accepted Answer

Some plant communities are adapted to grow in serpentine soils containing toxic elements.

The Chemical Context of Life Chapter 2

Guida di studio - Domande di pratica

Study guide - Flashcard