Question 1

An oxygen atom has ____ surrounding a nucleus composed of ____.

Accepted Answer

An oxygen atom, like all atoms, has electrons orbiting around its nucleus, which is composed of protons and neutrons.

Question 2

Ice floats in liquid water because there are, on average, fewer hydrogen bonds between molecules in ice than water, resulting in a lower density.

Accepted Answer

Ice floats in liquid water because there are more hydrogen bonds in ice, creating an open hexagonal structure that is less dense than liquid water.

Question 3

The four elements that make up more than 96.5% of the weight of living organisms are oxygen, carbon, hydrogen, and calcium.

Accepted Answer

The four elements that make up more than 96.5% of the weight of living organisms are oxygen, carbon, hydrogen, and nitrogen.

Question 4

Radioactive ____ is commonly used to treat patients with dangerously overactive thyroid glands.

Accepted Answer

Iodine, specifically radioactive iodine-131, is commonly used in the treatment of overactive thyroid glands (hyperthyroidism) because the thyroid gland absorbs iodine, allowing the radioactive iodine to target and destroy overactive thyroid cells.

Question 5

A trace element is one found in specific organisms in ____ quantities and is ____ for normal biological functions.

Accepted Answer

Trace elements are found in small quantities in organisms but are essential for normal biological functions.

Question 6

The smallest unit that retains the chemical and physical properties of an element is a(n) ____.

Accepted Answer

An atom is the smallest unit of an element that retains its chemical properties. Protons and neutrons are subatomic particles, not units of elements. A molecule is the smallest unit of a compound, not an element, and a compound consists of two or more elements chemically combined.

Question 7

Atoms with atomic numbers between lithium and neon have two energy levels.

Accepted Answer

Atoms with atomic numbers between lithium (3) and neon (10) have electrons in two energy levels: the first level (1s and 2s orbitals) and the second level (2p orbitals).

Question 8

Prolonged iodine deficiency causes ____, a condition in which the thyroid gland enlarges so much that the front of the neck swells significantly.

Accepted Answer

Prolonged iodine deficiency can lead to the development of a goiter, which is an enlargement of the thyroid gland causing a noticeable swelling in the front of the neck.

Question 9

Figure 2.1
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Answer the question using the accompanying figure. The mass number of the atom depicted in the figure is ____.

Accepted Answer

The mass number is the sum of protons and neutrons in the nucleus. The figure likely shows an atom with 6 protons and 6 neutrons, giving a mass number of 12.

Question 10

Carbon dioxide is an element.

Accepted Answer

Carbon dioxide is a compound consisting of one carbon atom and two oxygen atoms.

Question 11

In the representation of hydrogen gas, H-H, the dash represents two electrons being shared equally.

Accepted Answer

The dash in the representation of hydrogen gas (H-H) symbolizes a single covalent bond, which involves the sharing of two electrons, one from each hydrogen atom, to achieve a stable electron configuration.

Question 12

The substance H₂O is considered to be ____.

Accepted Answer

H₂O represents a chemical formula with multiple elements (H, S, U, B, O), indicating it is a compound. Since it is a distinct entity made of atoms bonded together, it is also a molecule.

Question 13

Acid precipitation can have a pH as low as 3.

Accepted Answer

Acid precipitation, such as acid rain, can indeed have a pH as low as 3, which is significantly more acidic than normal rainwater's pH of around 5.6, due to the presence of dissolved sulfuric and nitric acids formed from pollutants.

Question 14

Four elements, including ____, make up more than 96.5% of the mass of most living organisms.

Accepted Answer

Carbon, hydrogen, oxygen, and nitrogen are the four elements that make up more than 96.5% of the mass of most living organisms.

Question 15

Proteins in thermophiles must be stabilized by van der Waals forces, because hydrogen bonds cannot be maintained at high temperatures.

Accepted Answer

Hydrogen bonds are weakened at high temperatures, but van der Waals forces are not.

Question 16

Buffers can increase the pH of a solution when acids are added.

Accepted Answer

Buffers resist changes in pH by neutralizing added acids or bases, but they do not increase the pH when acids are added; they maintain it.

Question 17

The substance O₂is considered to be ____.

Accepted Answer

O₂ is a molecule because it consists of two oxygen atoms bonded together, but it is not a compound because a compound must consist of two or more different elements.

Question 18

Diluted acetic acid, CH₃COOH, is commonly called vinegar. How many atoms of hydrogen are present in one molecule of acetic acid?

Accepted Answer

Acetic acid (CH₃COOH) contains four hydrogen atoms: three in the methyl group (CH₃) and one in the carboxyl group (COOH).

Question 19

The polarity of water allows it to create a hydration layer that prevents salt from coming back out of solution after it has been dissolved.

Accepted Answer

Water's polarity enables it to surround and separate individual ions from a salt crystal, effectively dissolving it. The hydration layer around each ion prevents them from reassociating and coming out of solution, keeping the salt dissolved.

Question 20

Hydrogen, atomic number 1, has three isotopes,¹H,²H,³H.¹H is comprised of one proton, one neutron, and one electron.

Accepted Answer

Hydrogen-1 (Protium, $ ^1_1H $) has no neutrons, only one proton and one electron.

Quiz 2: Life, Chemistry, and Water

An oxygen atom has surrounding a nucleus composed of .

Ice floats in liquid water because there are, on average, fewer hydrogen bonds between molecules in ice than water, resulting in a lower density.

The four elements that make up more than 96.5% of the weight of living organisms are oxygen, carbon, hydrogen, and calcium.

Radioactive ____ is commonly used to treat patients with dangerously overactive thyroid glands.

A trace element is one found in specific organisms in quantities and is for normal biological functions.

The smallest unit that retains the chemical and physical properties of an element is a(n) ____.

Atoms with atomic numbers between lithium and neon have two energy levels.

Prolonged iodine deficiency causes ____, a condition in which the thyroid gland enlarges so much that the front of the neck swells significantly.

Figure 2.1 - Answer the question using the accompanying figure. The mass number of the atom depicted in the figure is ____.

Carbon dioxide is an element.

In the representation of hydrogen gas, H-H, the dash represents two electrons being shared equally.

The substance H₂O is considered to be ____.

Acid precipitation can have a pH as low as 3.

Four elements, including ____, make up more than 96.5% of the mass of most living organisms.

Proteins in thermophiles must be stabilized by van der Waals forces, because hydrogen bonds cannot be maintained at high temperatures.

Buffers can increase the pH of a solution when acids are added.

The substance O₂is considered to be ____.

Diluted acetic acid, CH₃COOH, is commonly called vinegar. How many atoms of hydrogen are present in one molecule of acetic acid?

The polarity of water allows it to create a hydration layer that prevents salt from coming back out of solution after it has been dissolved.

Hydrogen, atomic number 1, has three isotopes,¹H,²H,³H.¹H is comprised of one proton, one neutron, and one electron.

Quiz 2: Life, Chemistry, and Water

An oxygen atom has ____ surrounding a nucleus composed of ____.

Ice floats in liquid water because there are, on average, fewer hydrogen bonds between molecules in ice than water, resulting in a lower density.

The four elements that make up more than 96.5% of the weight of living organisms are oxygen, carbon, hydrogen, and calcium.

Radioactive ____ is commonly used to treat patients with dangerously overactive thyroid glands.

A trace element is one found in specific organisms in ____ quantities and is ____ for normal biological functions.

The smallest unit that retains the chemical and physical properties of an element is a(n) ____.

Atoms with atomic numbers between lithium and neon have two energy levels.

Prolonged iodine deficiency causes ____, a condition in which the thyroid gland enlarges so much that the front of the neck swells significantly.

Figure 2.1 - Answer the question using the accompanying figure. The mass number of the atom depicted in the figure is ____.

Carbon dioxide is an element.

In the representation of hydrogen gas, H-H, the dash represents two electrons being shared equally.

The substance H2O is considered to be ____.

Acid precipitation can have a pH as low as 3.

Four elements, including ____, make up more than 96.5% of the mass of most living organisms.

Proteins in thermophiles must be stabilized by van der Waals forces, because hydrogen bonds cannot be maintained at high temperatures.

Buffers can increase the pH of a solution when acids are added.

The substance O2is considered to be ____.

Diluted acetic acid, CH3COOH, is commonly called vinegar. How many atoms of hydrogen are present in one molecule of acetic acid?

The polarity of water allows it to create a hydration layer that prevents salt from coming back out of solution after it has been dissolved.

Hydrogen, atomic number 1, has three isotopes,1H,2H,3H.1H is comprised of one proton, one neutron, and one electron.

An oxygen atom has surrounding a nucleus composed of .

A trace element is one found in specific organisms in quantities and is for normal biological functions.

The substance H₂O is considered to be ____.

The substance O₂is considered to be ____.

Diluted acetic acid, CH₃COOH, is commonly called vinegar. How many atoms of hydrogen are present in one molecule of acetic acid?

Hydrogen, atomic number 1, has three isotopes,¹H,²H,³H.¹H is comprised of one proton, one neutron, and one electron.