Question 1

A pure substance composed of two or more different elements is a(n)________.

Accepted Answer

A chemical compound is a substance that contains two or more different elements in a fixed ratio. This definition fits the given description perfectly. Option A is incorrect because an ion is a charged particle that results from the loss or gain of electrons by an atom or molecule. Option B is incorrect because a heterogeneous mixture consists of visibly different substances or phases. Option D is incorrect because a solid can be a pure substance, but it does not necessarily have to be composed of multiple elements. Option E is incorrect because a solution is a homogeneous mixture of solute and solvent, and it can be a mixture of different substances rather than a pure substance.

Question 2

Which of the following is $\underline{\text{not  }}$  a correct name-symbol combination?

Accepted Answer

The correct symbol for potassium is K, not Ge.

Question 3

Which of the following observations is/are examples of physical change? 1)The density of water decreases when it solidifies. 2)Aluminum melts when heated above 660$^{\circ}$C. 3)Hydrogen peroxide (H₂O₂)decomposes to water and oxygen.

Accepted Answer

Physical changes involve changes in physical properties without altering the chemical composition. Both the decrease in density of water when it solidifies and the melting of aluminum are physical changes. The decomposition of hydrogen peroxide is a chemical change.

Question 4

Which of the following statements concerning water (H₂O) is/are CORRECT? 1) H₂O is a chemical compound. 2) Water is a homogeneous mixture. 3) Liquid water is a mixture of elemental hydrogen and oxygen.

Accepted Answer

Statement 1 is true as water (H₂O) is a chemical compound made up of hydrogen and oxygen elements. Statement 2 is false as water is a pure substance and not a mixture. Statement 3 is false as liquid water is not a mixture of elemental hydrogen and oxygen, but rather a combination of hydrogen and oxygen atoms in a specific ratio to form water molecules.

Question 5

Which one of the following statements is not a comparison of physical properties?

Accepted Answer

Statement A is comparing the chemical reactions of two elements, rather than their physical properties. The other statements are comparing physical properties such as conductivity, density, solubility, and boiling point.

Question 6

Which one of the following statements is not a comparison of physical properties?

Accepted Answer

The answer of Which one of the following statements is...

Question 7

All of the following are examples of intensive properties of matter EXCEPT _______.

Accepted Answer

Weight is an example of an extensive property of matter, as it depends on the amount (or quantity) of matter present. Intensive properties, on the other hand, do not depend on the quantity of matter present. Choices A, B, and C are examples of intensive properties. Choice E is also an example of an intensive property, as malleability refers to a substance's ability to be shaped under pressure, regardless of the amount of substance present.

Question 8

An electrically charged atom or group of atoms is a(n)________.

Accepted Answer

An ion is an electrically charged atom or group of atoms, either positively or negatively charged, due to the loss or gain of one or more electrons.

Question 9

Which of the following observations is/are examples of chemical change? 1)Iron (Fe)rusts,forming Fe₂O₃. 2)The density of water increases when it changes from a solid to a liquid. 3)Sodium chloride melts at 801$^{\circ}$C.

Accepted Answer

Observation 1 involves a chemical change, as iron (Fe) reacts with oxygen (O) to form rust (Fe₂O₃). Observation 2 is a physical change, as the density of water changes due to a phase transition from solid to liquid. Observation 3 is also a physical change, as sodium chloride (NaCl) undergoes a phase transition from solid to liquid at a specific temperature.

Question 10

An intensive property of a substance is

Accepted Answer

An intensive property is a physical property that does not depend on the amount of substance present. Examples of intensive properties include temperature, density, and specific heat. Therefore, choice A is the correct answer.

Question 11

Which of following would be classified as a $\underline{\text{  chemical }}$  change?

Accepted Answer

Tarnishing of the surface of copper in the presence of oxygen is a chemical change because it involves a reaction between copper and oxygen, leading to the formation of new compounds on the surface of the metal. The other options are physical changes where no new substances are formed.

Question 12

What is the name of the element with the symbol Cr?

Accepted Answer

The symbol Cr stands for the element chromium.

Question 13

Which one of the following substances is classified as a chemical compound?

Accepted Answer

CO (carbon monoxide) is a chemical compound composed of two different elements, carbon and oxygen, while Mo, Cr, Cd, and No are chemical elements themselves.

Question 14

What kind of change is depicted below?

Accepted Answer

The answer of What kind of change is depicted below?...

Question 15

Which of the following are extensive properties: mass,volume,and/or density?

Accepted Answer

Mass and volume are both extensive properties because they depend on the size or amount of the substance present. Density, on the other hand, is an intensive property because it is a ratio of mass to volume and does not depend on the size of the substance.

Question 16

A(n)________ is a pure substance that is composed of only one type of atom.

Accepted Answer

An element is a pure substance made up of only one type of atom, therefore it is the best choice.

Question 17

Which one of the following substances is classified as an element?

Accepted Answer

I₂ is iodine, which is a diatomic molecule consisting of two atoms of the same element, making it an element. The other options are compounds.

Question 18

Which term best describes methane,CH₄?

Accepted Answer

Methane is a compound as it is composed of two or more different elements chemically combined in a fixed ratio.

Question 19

Which of the following statements is/are CORRECT?
1)The conduction of electricity through copper wire is a chemical change.
2)The rusting of iron is a chemical change.
3)The evaporation of ammonia at -33.3$^{\circ}$C is a chemical change.

Accepted Answer

1) The conduction of electricity through copper wire is a physical change as it does not change the chemical composition of copper.
2) The rusting of iron is a chemical change as it involves a chemical reaction between iron, water, and oxygen which results in the formation of a new substance (iron oxide).
3) The evaporation of ammonia at -33.3°F/-36°C is a physical change as it does not involve any chemical reaction or change in the chemical composition of ammonia.

Question 20

A battery-operated power tool,such as a cordless drill,converts

Accepted Answer

A battery contains chemical potential energy, which is converted into electrical energy when it is used in a power tool like a cordless drill. The electrical energy is then converted into mechanical energy to provide power to the drill. Therefore, choice E, chemical potential energy to mechanical energy, is the best choice.

Quiz 1: Basic Concepts of Chemistry

A pure substance composed of two or more different elements is a(n) ________.

Which of the following is $\underline{\text{not }}$ a correct name-symbol combination?

Which of the following observations is/are examples of physical change? 1) The density of water decreases when it solidifies. 2) Aluminum melts when heated above 660 $^{\circ}$ C. 3) Hydrogen peroxide (H₂O₂) decomposes to water and oxygen.

Which of the following statements concerning water (H₂O) is/are CORRECT? 1) H₂O is a chemical compound. 2) Water is a homogeneous mixture. 3) Liquid water is a mixture of elemental hydrogen and oxygen.

Which one of the following statements is not a comparison of physical properties?

Which one of the following statements is not a comparison of physical properties?

All of the following are examples of intensive properties of matter EXCEPT _______.

An electrically charged atom or group of atoms is a(n) ________.

Which of the following observations is/are examples of chemical change? 1) Iron (Fe) rusts,forming Fe₂O₃. 2) The density of water increases when it changes from a solid to a liquid. 3) Sodium chloride melts at 801 $^{\circ}$ C.

An intensive property of a substance is

Which of following would be classified as a $\underline{\text{ chemical }}$ change?

What is the name of the element with the symbol Cr?

Which one of the following substances is classified as a chemical compound?

What kind of change is depicted below?

Which of the following are extensive properties: mass,volume,and/or density?

A(n) ________ is a pure substance that is composed of only one type of atom.

Which one of the following substances is classified as an element?

Which term best describes methane,CH₄?

Which of the following statements is/are CORRECT? 1) The conduction of electricity through copper wire is a chemical change. 2) The rusting of iron is a chemical change. 3) The evaporation of ammonia at -33.3 $^{\circ}$ C is a chemical change.

A battery-operated power tool,such as a cordless drill,converts

Quiz 1: Basic Concepts of Chemistry

A pure substance composed of two or more different elements is a(n) ________.

Which of the following is not ‾\underline{\text{not }}not ​ a correct name-symbol combination?

Which of the following observations is/are examples of physical change? 1) The density of water decreases when it solidifies. 2) Aluminum melts when heated above 660 ∘^{\circ}∘ C. 3) Hydrogen peroxide (H2O2) decomposes to water and oxygen.

Which of the following statements concerning water (H2O) is/are CORRECT? 1) H2O is a chemical compound. 2) Water is a homogeneous mixture. 3) Liquid water is a mixture of elemental hydrogen and oxygen.

Which one of the following statements is not a comparison of physical properties?

Which one of the following statements is not a comparison of physical properties?

All of the following are examples of intensive properties of matter EXCEPT _______.

An electrically charged atom or group of atoms is a(n) ________.

Which of the following observations is/are examples of chemical change? 1) Iron (Fe) rusts,forming Fe2O3. 2) The density of water increases when it changes from a solid to a liquid. 3) Sodium chloride melts at 801 ∘^{\circ}∘ C.

An intensive property of a substance is

Which of following would be classified as a chemical ‾\underline{\text{ chemical }} chemical ​ change?

What is the name of the element with the symbol Cr?

Which one of the following substances is classified as a chemical compound?

What kind of change is depicted below?

Which of the following are extensive properties: mass,volume,and/or density?

A(n) ________ is a pure substance that is composed of only one type of atom.

Which one of the following substances is classified as an element?

Which term best describes methane,CH4?

Which of the following statements is/are CORRECT? 1) The conduction of electricity through copper wire is a chemical change. 2) The rusting of iron is a chemical change. 3) The evaporation of ammonia at -33.3 ∘^{\circ}∘ C is a chemical change.

A battery-operated power tool,such as a cordless drill,converts

Which of the following is $\underline{\text{not }}$ a correct name-symbol combination?

Which of the following observations is/are examples of physical change? 1) The density of water decreases when it solidifies. 2) Aluminum melts when heated above 660 $^{\circ}$ C. 3) Hydrogen peroxide (H₂O₂) decomposes to water and oxygen.

Which of the following statements concerning water (H₂O) is/are CORRECT? 1) H₂O is a chemical compound. 2) Water is a homogeneous mixture. 3) Liquid water is a mixture of elemental hydrogen and oxygen.

Which of the following observations is/are examples of chemical change? 1) Iron (Fe) rusts,forming Fe₂O₃. 2) The density of water increases when it changes from a solid to a liquid. 3) Sodium chloride melts at 801 $^{\circ}$ C.

Which of following would be classified as a $\underline{\text{ chemical }}$ change?

Which term best describes methane,CH₄?

Which of the following statements is/are CORRECT? 1) The conduction of electricity through copper wire is a chemical change. 2) The rusting of iron is a chemical change. 3) The evaporation of ammonia at -33.3 $^{\circ}$ C is a chemical change.