chpt 2

Question 1

What is matter?

Answer 1

Anything that occupies space and has mass.

Question 2

Which of the following statements about mass and weight is true?

Answer 2

Weight changes with gravity, while mass remains the same.

Question 3

Why does an object weigh less on the moon than on Earth?

Answer 3

The moon has less gravity than Earth.

Question 4

What is an element?

Answer 4

A pure substance that cannot be created or broken down by ordinary chemical means.

Question 5

Which of the following is an example of an element?

Answer 5

Calcium.

Question 6

How does the human body obtain elements?

Answer 6

From the environment through food and air.

Question 7

What elements are the most abundant in the human body?

Answer 7

Oxygen, carbon, hydrogen, and nitrogen.

Question 8

What is a compound?

Answer 8

A substance composed of two or more elements joined by chemical bonds.

Question 9

Which of the following compounds is important as a body fuel?

Answer 9

Glucose.

Question 10

What is the smallest quantity of an element that retains its unique properties?

Answer 10

An atom.

Question 11

What subatomic particles contribute to the mass of an atom?

Answer 11

Protons and neutrons.

Question 12

Which subatomic particle determines the element of an atom?

Answer 12

Proton.

Question 13

How does the mass of an electron compare to that of a proton or neutron?

Answer 13

About 1/2000th the mass.

Question 14

In the electron cloud model, electrons:

Answer 14

Move erratically within a cloud-like region.

Question 15

What is the atomic number of an element?

Answer 15

The number of protons.

Question 16

Which statement is true about isotopes?

Answer 16

They differ in the number of neutrons.

Question 17

What is a heavy isotope?

Answer 17

An isotope with more neutrons than usual.

Question 18

What is the half-life of a radioactive isotope?

Answer 18

The time it takes for half of the sample to decay.

Question 19

Which medical imaging technique uses radioactive glucose to detect tissue activity?

Answer 19

PET Scan.

Question 20

In radioembolization, tiny radioactive seeds are used to:

Answer 20

Kill tumor cells by disrupting their blood supply.

Question 21

What is the key difference between a molecule and a compound?

Answer 21

A molecule can be made of the same element, while a compound consists of different elements.

Question 22

Which of the following best defines an ion?

Answer 22

An atom that has gained or lost electrons, resulting in a charge.

Question 23

What is a cation?

Answer 23

A positively charged ion.

Question 24

Which statement correctly describes an anion?

Answer 24

An atom that has gained one or more electrons, becoming negatively charged.

Question 25

What distinguishes an ionic bond from a covalent bond?

Answer 25

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 26

In a polar covalent bond:

Answer 26

Electrons are shared unequally, creating partial charges.

Question 27

What characterizes a nonpolar covalent bond?

Answer 27

Equal sharing of electrons between atoms.

Question 28

How do water molecules link to each other?

Answer 28

Through hydrogen bonds.

Question 29

Why do atoms never actually touch each other?

Answer 29

Due to the electrical repulsion between their negatively charged electrons.

Question 30

Which of the following is an example of an ionic bond?

Answer 30

The bond between sodium (Na+) and chloride (Cl-) in table salt.

Question 31

What characteristic defines a nonpolar covalent bond?

Answer 31

Equal sharing of electrons.

Question 32

Why are nonpolar molecules electrically balanced?

Answer 32

The electrical pull of protons is equal across the molecule.

Question 33

What is a polar molecule?

Answer 33

A molecule with regions of opposite electrical charges.

Question 34

Which of the following is the most familiar example of a polar molecule?

Answer 34

Water.

Question 35

In a water molecule, why are electrons more strongly attracted to the oxygen atom?

Answer 35

Oxygen's nucleus contains more protons, exerting a stronger positive charge.

Question 36

What type of charge is present on the oxygen region of a water molecule?

Answer 36

Slightly negative (partial negative charge).

Question 37

What does the Greek letter delta (δ) represent in chemical diagrams?

Answer 37

Partial charges.

Question 38

What is a dipole in the context of water molecules?

Answer 38

A molecule with positive and negative charges at opposite ends.

Question 39

Which of the following best describes a hydrogen bond?

Answer 39

An attraction between a weakly positive hydrogen and an electronegative atom.

Question 40

Why do hydrogen bonds form between water molecules?

Answer 40

Due to the attraction between weakly positive hydrogen atoms and weakly negative oxygen atoms.

Question 41

What type of line is used to represent hydrogen bonds in diagrams?

Answer 41

Dashed or dotted line.

Question 42

Why does table salt dissolve easily in water?

Answer 42

Water forms dipole-ion bonds with sodium and chloride ions.

Question 43

What happens when you add vegetable oil to water?

Answer 43

The oil forms a distinct bead because water repels nonpolar oil molecules.

Question 44

What types of molecules do water molecules repel?

Answer 44

Nonpolar covalent molecules like fats and oils.

Question 45

Which of the following best explains the importance of hydrogen bonds in human physiology?

Answer 45

They help water molecules interact with other polar molecules, playing a key role in biological processes.