Question 1

In which of the following sequences of elements does each of the elements have a one-letter chemical symbol?
A) indium, carbon, silver
B) iodine, boron, tungsten
C) antimony, boron, nitrogen
D) nitrogen, germanium, bromine

Accepted Answer

B) iodine (I), boron (B), and tungsten (W) all have one-letter chemical symbols.

Question 2

Which one of the following statements about heteroatomic molecules is correct?
A) No two atoms in a heteroatomic molecule may be the same.
B) Upon chemical subdivision, heteroatomic molecules always yield two or more kinds of atoms.
C) Heteroatomic molecules maintain the properties of their constituent elements.
D) Molecules of certain elements are heteroatomic.

Accepted Answer

Heteroatomic molecules are molecules composed of two or more different types of atoms. Upon chemical subdivision or decomposition, these molecules will always yield two or more kinds of atoms. Therefore, statement B is correct. Statement A is incorrect because there can be heteroatomic molecules with two or more atoms of the same element, such as carbon dioxide (CO2). Statement C is also incorrect because heteroatomic molecules may have different properties from their constituent elements due to their unique chemical bonding arrangements. Statement D is incomplete and does not make a definitive statement, so it cannot be determined whether it is correct or incorrect.

Question 3

Which of the following statements about heterogeneous and homogeneous mixtures is correct?
A) It is possible to have heterogeneous mixtures in which all the components are liquids.
B) A homogeneous mixture contains visibly different parts, or phases.
C) All of the phases in a heterogeneous mixture must be in the same state.
D) No two phases in a heterogeneous mixture can be in the same state.

Accepted Answer

A heterogeneous mixture can be made up of all liquids, gases, or solids, and the components are not evenly distributed throughout the mixture.

Question 4

In which of the following pairs of chemical formulas do the two members of the pair contain the same number of elements as well as the same number of atoms? A) Cs and CS B) CoBr₂ and COBr₂ C) CoCl₂ and CoCl₃ D) NH₄Br and NiSO₄

Accepted Answer

The answer of In which of the following pairs of...

Question 5

Which of the following statements is correct?
A) Elements, but not compounds, are pure substances.
B) Compounds, but not elements, are pure substances.
C) Both elements and compounds are pure substances.
D) Neither elements nor compounds are pure substances.

Accepted Answer

Both elements and compounds are considered pure substances because they consist of only one type of atom or molecule, respectively.

Question 6

In which of the following pairs of chemical formulas do both formulas represent compounds? A) O₂ and O₃ B) CO₂ and O₂ C) HCN and N₂ D) N₂O₄ and NO₂

Accepted Answer

N₂O₄ and NO₂ are both compounds, while O₂, O₃, and N₂ are elements. CO₂ and HCN are compounds, but O₂ and N₂ are not.

Question 7

In which of the following pairs of properties are both properties chemical properties?
A) freezes at 10$\degree$C and nonflammable
B) decomposes at 500$\degree$C and reacts with bromine
C) poor conductor of heat and is reddish brown in color
D) has a low density and is very hard

Accepted Answer

Both properties, decomposing at 500°F and reacting with bromine, involve chemical changes or reactions. The other choices describe physical properties such as freezing point, color, density, and hardness.

Question 8

Which of the following is a property of both gases and liquids?
A) definite shape
B) indefinite shape
C) definite volume
D) indefinite volume

Accepted Answer

Both gases and liquids take the shape of their container, meaning they have an indefinite shape.

Question 9

Which one of the following statements about atoms is incorrect?
A) An atom is the smallest "piece" of an element that can exist and still have the properties of the element.
B) Free isolated atoms are rarely encountered in nature.
C) Atoms may be decomposed using chemical change.
D) Only one kind of atom may be present in a homoatomic molecule.

Accepted Answer

Atoms cannot be decomposed using chemical change. Chemical reactions only rearrange the atoms and molecules present, but no atoms are created or destroyed. Only nuclear reactions can change the composition of an atom.

Question 10

The total number of atoms present in one formula unit of Co₂(SO₄)₃ is A) 14 B) 15 C) 16 D) 17

Accepted Answer

The answer of The total number of atoms present in...

Question 11

In which of the following sequences of elements does each of the elements have a two-letter chemical symbol?
A) barium, iron, nitrogen
B) selenium, nickel, strontium
C) silicon, zinc, hydrogen
D) iodine, xenon, titantium

Accepted Answer

The chemical symbols for the elements in sequence B are Se (selenium), Ni (nickel), and Sr (strontium), each of which has a two-letter chemical symbol. The other sequences have at least one element with a one-letter symbol (Fe for iron in A, N for nitrogen in A, Zn for zinc in C, H for hydrogen in C, I for iodine in D, and Xe for xenon in D) or a longer symbol (Ti for titanium in D).

Question 12

A pure substance F is found to change upon heating into two new pure substances M and Y. Both M and Y may be decomposed by chemical means. From this we may conclude that:
A) F is an element, M and Y are compounds.
B) F is a compound, M and Y are elements.
C) F, M and Y are all elements.
D) F, M and Y are all compounds.

Accepted Answer

F is a compound because it decomposes into two new substances, M and Y, upon heating. M and Y are also compounds because they can be further decomposed by chemical means.

Question 13

An element is a substance that
A) can be broken down into simpler substances by physical means.
B) cannot be broken down into simpler substances by physical means.
C) can be broken down into simpler substances by chemical means.
D) cannot be broken down into simpler substances by chemical or physical means.

Accepted Answer

An element is a fundamental substance that cannot be broken down into simpler substances by either chemical or physical means. It is composed of atoms all having the same number of protons.

Question 14

The most abundant elements in the universe and the Earth's crust are, respectively,
A) oxygen and iron.
B) hydrogen and helium.
C) helium and carbon.
D) hydrogen and oxygen.

Accepted Answer

Hydrogen is the most abundant element in the universe, primarily due to its presence in stars, including the Sun. Oxygen is the most abundant element in the Earth's crust, found in water and many minerals.

Question 15

Which of the following is a correct description for a sample of ice cubes in water?
A) one phase present, one substance present
B) one phase present, two substances present
C) two phases present, one substance present
D) two phases present, two substances present

Accepted Answer

A sample of ice cubes in water contains two phases - solid ice and liquid water, but only one substance, which is water.

Question 16

When a substance undergoes a chemical change it is always true that
A) it liquifies
B) it changes from a solid to a gas
C) it is converted to a new kind of matter with a different composition
D) the temperature of the substance increases

Accepted Answer

When a substance undergoes a chemical change, its atoms rearrange to form new molecules with different properties and a different composition. This means that the substance is no longer the same kind of matter it was before the change. Liquification, change from solid to gas, and temperature increase may or may not occur during a chemical change, depending on the specific reaction.

Question 17

Which of the following pairings of chemical formulas and "molecular descriptions" is incorrect? A) LiCN and "triatomic" B) KCl and "heteroatomic" C) N₂ and "homoatomic" D) SiO₂ and "diatomic"

Accepted Answer

SiO₂ should be SiO2, which is a triatomic molecule, not diatomic.

Question 18

The description "two substances present, two phases present" is correct for
A) heterogeneous mixtures
B) homogeneous mixtures
C) elements
D) compounds

Accepted Answer

In a heterogeneous mixture, different substances are present in different phases, which can be seen by the naked eye. Therefore, the description "two substances present, two phases present" is correct for heterogeneous mixtures. Homogeneous mixtures, elements, and compounds would only have one phase present.

Question 19

Which of the following statements concerning the known elements is correct?
A) No new elements have been identified within the last 40 years.
B) Most elements occur naturally.
C) 108 elements are known at present
D) Scientists have synthesized all possible non-natural elements.

Accepted Answer

Currently, 118 elements are known, and new elements have been identified within the last 40 years (the most recent being tennessine in 2010). While some elements do occur naturally, others have been synthesized by scientists. However, it is not possible to synthesize all possible non-natural elements as the properties of such elements may be beyond the reach of current technology.

Question 20

Consider the chemical formulas CoI₂ and COI₂. It is true that they A) contain identical kinds of atoms B) identify the same compound C) contain different kinds and numbers of atoms D) can be described by none of the above

Accepted Answer

The two formulas differ in the capitalization of the element symbol for cobalt (Co). This means they are two different compounds, even though they contain the same kinds and numbers of atoms. In general, the capitalization of element symbols matters, as it signifies different chemical species.

Quiz 1: Basic Concepts About Matter

In which of the following sequences of elements does each of the elements have a one-letter chemical symbol?

Which one of the following statements about heteroatomic molecules is correct?

Which of the following statements about heterogeneous and homogeneous mixtures is correct?

In which of the following pairs of chemical formulas do the two members of the pair contain the same number of elements as well as the same number of atoms?

Which of the following statements is correct?

In which of the following pairs of chemical formulas do both formulas represent compounds?

In which of the following pairs of properties are both properties chemical properties?

Which of the following is a property of both gases and liquids?

Which one of the following statements about atoms is incorrect?

The total number of atoms present in one formula unit of Co₂(SO₄) ₃ is

In which of the following sequences of elements does each of the elements have a two-letter chemical symbol?

A pure substance F is found to change upon heating into two new pure substances M and Y. Both M and Y may be decomposed by chemical means. From this we may conclude that:

An element is a substance that

The most abundant elements in the universe and the Earth's crust are, respectively,

Which of the following is a correct description for a sample of ice cubes in water?

When a substance undergoes a chemical change it is always true that

Which of the following pairings of chemical formulas and "molecular descriptions" is incorrect?

The description "two substances present, two phases present" is correct for

Which of the following statements concerning the known elements is correct?

Consider the chemical formulas CoI₂ and COI₂. It is true that they