Question 1

Oxygen-16 is abundant and has 8 protons and 8 neutrons.Oxygen-18 has two extra neutrons.These two forms are:

Accepted Answer

Oxygen-16 and Oxygen-18 are isotopes because they have the same number of protons but different numbers of neutrons.

Question 2

Plants transport water to their leaves through the xylem when water evaporates from the leaves.The evaporating water pulls other water molecules up the xylem through ____ .

Accepted Answer

Water molecules are pulled up the xylem through hydrogen bonds, which create cohesion between the molecules.

Question 3

Life is thought to have evolved from complex molecules formed by the interaction of smaller molecules in oceans and the atmosphere.The substance which brought these molecules together to interact is

Accepted Answer

Water is a solvent that facilitates the interaction and reaction of molecules, making it essential for the formation of complex molecules necessary for life.

Question 4

Atoms in which the number of electrons does not equal the number of protons are known as:

Accepted Answer

Atoms in which the number of electrons does not equal the number of protons are known as ions. This is because the atoms have a net electrical charge due to an excess or deficit of electrons.

Question 5

In the crystal matrix of ordinary salt, the sodium and chlorine are held together by:

Accepted Answer

Ionic bonds are formed between sodium and chlorine atoms in the crystal matrix of ordinary salt.

Question 6

Sodium has 11 electrons arranged in three energy levels.In order to become stable, sodium forms an ion with:

Accepted Answer

Sodium loses one electron to achieve a stable electron configuration, resulting in a +1 charge.

Question 7

The pH of your small intestines is around 7.5 and the pH of your large intestine can be 5.5.As substances travel from the small intestines to the large intestine, what would happen to the H⁺ ion concentration?

Accepted Answer

The pH decreases from 7.5 to 5.5, indicating an increase in H⁺ ion concentration by 100 fold, as each pH unit represents a tenfold change in H⁺ ion concentration.

Question 8

Mendeleev found that when he arranged the known elements according to their atomic mass, the entries in the table exhibited a pattern of chemical properties that repeated itself in groups of eight elements.This led to the generalization now known as:

Accepted Answer

The answer of Mendeleev found that when he arranged the...

Question 9

Oxygen has an atomic mass of 16 and an atomic number of 8.How many neutrons are present?

Accepted Answer

Atomic mass - atomic number = number of neutrons16 - 8 = 8

Question 10

Two oxygen atoms joined to each other by the sharing of two pairs of electrons form a(n):

Accepted Answer

A double covalent bond is formed when two atoms share two pairs of electrons. In the case of two oxygen atoms, they share two pairs of electrons to achieve a stable electron configuration, resulting in a double covalent bond.

Question 11

Nitrogen has a higher electronegativity than hydrogen.As a result you would expect that ammonia (NH₃) molecules can form ____ with each other.

Accepted Answer

Ammonia molecules can form hydrogen bonds with each other due to the high electronegativity of nitrogen, which creates a partial negative charge, allowing it to attract the hydrogen atoms of neighboring ammonia molecules.

Question 12

Water is most dense and thus heaviest at 4 $\degree$C.At 0 $\degree$C, ice forms and the ice can float on liquid water.Suppose ice were more dense than water at 0 ^$\degree$ C.What would happen in a lake at this temperature?

Accepted Answer

If ice were more dense than water, it would sink to the bottom of the lake, accumulating in layers over time.

Question 13

How many hydrogen bonds can a water molecule form?

Accepted Answer

A water molecule can form up to four hydrogen bonds: two through its hydrogen atoms and two through its lone pairs on the oxygen atom.

Question 14

The area around a nucleus where an electron is most likely to be found is the:

Accepted Answer

The area around a nucleus where an electron is most likely to be found is called an orbital. Energy levels refer to the specific energy states that electrons can occupy, but do not indicate the actual location of the electron. Electrical space and polar space are not terms commonly used in relation to electron location in an atom.

Question 15

Regardless of its shape, a given orbital may contain no more than:

Accepted Answer

According to the Pauli exclusion principle, each orbital can only hold a maximum of two electrons with opposite spins.

Question 16

Which element's isotope is commonly used to determine when biological samples such as fossils, were formed?

Accepted Answer

Carbon, specifically the isotope carbon-14, is commonly used in radiocarbon dating to determine the age of biological samples such as fossils.

Question 17

All atoms tend to fill their outer energy levels with the maximum number of electrons, usually eight.Depending on whether atoms satisfy the octet rule will predict:

Accepted Answer

The octet rule determines the stability of atoms and their tendency to form bonds with other atoms to fulfill the rule. This influences the chemical behavior of the atoms. The other options are not directly related to the octet rule.

Question 18

Water molecules are attracted to each other due to the opposite charges created by partial charge separations within the molecules.These attractions are called:

Accepted Answer

Water molecules are attracted to each other through hydrogen bonds, which occur due to the partial positive charge on the hydrogen atoms and the partial negative charge on the oxygen atom within the water molecule.

Question 19

A scientist conducts a procedure that causes nitrogen atoms to gain neutrons.The resulting atoms will be:

Accepted Answer

When nitrogen atoms gain neutrons, they become isotopes of nitrogen, as isotopes are atoms of the same element with different numbers of neutrons.

Question 20

The half-life of Carbon-14 is approximately 5,700 years.Using this information scientists have been able to determine the age of some artifacts left by humans.A scientist wants to know approximately how old a piece of wood was that she found on the floor in an old cave that had recently been discovered.She removed the wood (with permission) to her laboratory.Her wood sample contained 2 grams of Carbon-14.If the age of the wood was determined to be 22,800 years old, how much Carbon-14 originally existed in this piece of wood?

Accepted Answer

The amount of Carbon-14 remaining after 22,800 years is 2 grams. The half-life of Carbon-14 is 5,700 years, so after 22,800 years, there would be 2^4 = 16 grams of Carbon-14 remaining. Therefore, the original amount of Carbon-14 in the wood was 16 grams.

Quiz 2: The Nature of Molecules and the Properties of Water

Oxygen-16 is abundant and has 8 protons and 8 neutrons.Oxygen-18 has two extra neutrons.These two forms are:

Plants transport water to their leaves through the xylem when water evaporates from the leaves.The evaporating water pulls other water molecules up the xylem through ____ .

Life is thought to have evolved from complex molecules formed by the interaction of smaller molecules in oceans and the atmosphere.The substance which brought these molecules together to interact is

Atoms in which the number of electrons does not equal the number of protons are known as:

In the crystal matrix of ordinary salt, the sodium and chlorine are held together by:

Sodium has 11 electrons arranged in three energy levels.In order to become stable, sodium forms an ion with:

The pH of your small intestines is around 7.5 and the pH of your large intestine can be 5.5.As substances travel from the small intestines to the large intestine, what would happen to the H⁺ ion concentration?

Mendeleev found that when he arranged the known elements according to their atomic mass, the entries in the table exhibited a pattern of chemical properties that repeated itself in groups of eight elements.This led to the generalization now known as:

Oxygen has an atomic mass of 16 and an atomic number of 8.How many neutrons are present?

Two oxygen atoms joined to each other by the sharing of two pairs of electrons form a(n) :

Nitrogen has a higher electronegativity than hydrogen.As a result you would expect that ammonia (NH₃) molecules can form ____ with each other.

Water is most dense and thus heaviest at 4 $\degree$ C.At 0 $\degree$ C, ice forms and the ice can float on liquid water.Suppose ice were more dense than water at 0 ^$\degree$ C.What would happen in a lake at this temperature?

How many hydrogen bonds can a water molecule form?

The area around a nucleus where an electron is most likely to be found is the:

Regardless of its shape, a given orbital may contain no more than:

Which element's isotope is commonly used to determine when biological samples such as fossils, were formed?

All atoms tend to fill their outer energy levels with the maximum number of electrons, usually eight.Depending on whether atoms satisfy the octet rule will predict:

Water molecules are attracted to each other due to the opposite charges created by partial charge separations within the molecules.These attractions are called:

A scientist conducts a procedure that causes nitrogen atoms to gain neutrons.The resulting atoms will be:

Quiz 2: The Nature of Molecules and the Properties of Water

Oxygen-16 is abundant and has 8 protons and 8 neutrons.Oxygen-18 has two extra neutrons.These two forms are:

Plants transport water to their leaves through the xylem when water evaporates from the leaves.The evaporating water pulls other water molecules up the xylem through ____ .

Life is thought to have evolved from complex molecules formed by the interaction of smaller molecules in oceans and the atmosphere.The substance which brought these molecules together to interact is

Atoms in which the number of electrons does not equal the number of protons are known as:

In the crystal matrix of ordinary salt, the sodium and chlorine are held together by:

Sodium has 11 electrons arranged in three energy levels.In order to become stable, sodium forms an ion with:

The pH of your small intestines is around 7.5 and the pH of your large intestine can be 5.5.As substances travel from the small intestines to the large intestine, what would happen to the H+ ion concentration?

Mendeleev found that when he arranged the known elements according to their atomic mass, the entries in the table exhibited a pattern of chemical properties that repeated itself in groups of eight elements.This led to the generalization now known as:

Oxygen has an atomic mass of 16 and an atomic number of 8.How many neutrons are present?

Two oxygen atoms joined to each other by the sharing of two pairs of electrons form a(n) :

Nitrogen has a higher electronegativity than hydrogen.As a result you would expect that ammonia (NH3) molecules can form ____ with each other.

Water is most dense and thus heaviest at 4 °\degree° C.At 0 °\degree° C, ice forms and the ice can float on liquid water.Suppose ice were more dense than water at 0 °\degree° C.What would happen in a lake at this temperature?

How many hydrogen bonds can a water molecule form?

The area around a nucleus where an electron is most likely to be found is the:

Regardless of its shape, a given orbital may contain no more than:

Which element's isotope is commonly used to determine when biological samples such as fossils, were formed?

All atoms tend to fill their outer energy levels with the maximum number of electrons, usually eight.Depending on whether atoms satisfy the octet rule will predict:

Water molecules are attracted to each other due to the opposite charges created by partial charge separations within the molecules.These attractions are called:

A scientist conducts a procedure that causes nitrogen atoms to gain neutrons.The resulting atoms will be:

The pH of your small intestines is around 7.5 and the pH of your large intestine can be 5.5.As substances travel from the small intestines to the large intestine, what would happen to the H⁺ ion concentration?

Nitrogen has a higher electronegativity than hydrogen.As a result you would expect that ammonia (NH₃) molecules can form ____ with each other.

Water is most dense and thus heaviest at 4 $\degree$ C.At 0 $\degree$ C, ice forms and the ice can float on liquid water.Suppose ice were more dense than water at 0 ^$\degree$ C.What would happen in a lake at this temperature?