Basic Concepts About Matter - · PDF file1.4 Changes in matter ... composition, and transformations of matter Chemistry . Chemistry: The Study of Matter Return to TOC Section 1.1

Chapter 1

Basic Concepts About Matter

Chapter 1

Chapter Outline

Copyright ©2016 Cengage Learning. All Rights Reserved. 2

1.1 Chemistry: The study of matter 1.2 Physical states of matter 1.3 Properties of matter 1.4 Changes in matter 1.5 Pure substances and mixtures 1.6 Elements and compounds 1.7 Discovery and abundance of the elements 1.8 Names and chemical symbols of the elements 1.9 Atoms and molecules 1.10 Chemical formulas

Chemistry: The Study of Matter

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Section 1.1


•  Field of study concerned with the characteristics, composition, and transformations of matter

Chemistry


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Section 1.1


•  Anything that has mass and occupies space –  Mass - Amount of matter present in a sample

•  Includes naturally occurring living and nonliving things and synthetic materials –  Examples: Plants, soil, rocks, air, bacteria, plastics

•  Forms of energy such as heat, light, and electricity are not considered to be matter

•  Universe is composed entirely of matter and energy

Matter


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Section 1.1

Chemistry involves the study of matter. Which statement best describes matter? a. Matter includes various forms of energy. b. Matter is visible to the naked eye. c. Matter is anything that has mass and occupies space. d. No correct responses.



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Section 1.1

Chemistry involves the study of matter. Which statement best describes matter? a. Matter includes various forms of energy. b. Matter is visible to the naked eye. c. Matter is anything that has mass and occupies space. d. No correct responses.


Section 1.2

Physical States of Matter

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•  Classification is based on whether the shape and volume of the matter sample are definite or indefinite –  Solid –  Liquid –  Gas

Section 1.2


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•  Characterized by a definite shape and a definite volume

Solid

Section 1.2


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•  Characterized by an indefinite shape and a definite volume

•  Takes the shape of its container to the extent that it fills the container

Liquid

Section 1.2


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•  Characterized by an indefinite shape and volume

•  Completely fills its container, adopting both the container’s volume and its shape

Gas

Section 1.2


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Figure 1.1 - A Comparison of the Volume and Shape Characteristics of Solids, Liquids, and Gases

Section 1.2


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•  State of matter of a particular substance depends on: –  Temperature –  Surrounding pressure –  Strength of the forces holding its structural particles

together

Section 1.2


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The physical states of matter are: a.  solid, liquid, and gas. b.  solid, liquid, and heat. c.  solid, liquid, and electricity. d.  liquid, electricity, and heat.


Section 1.2


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The physical states of matter are: a.  solid, liquid, and gas. b.  solid, liquid, and heat. c.  solid, liquid, and electricity. d.  liquid, electricity, and heat.


Section 1.3

Properties of Matter

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•  Distinguishing characteristic of a substance that is used in its identification and description –  Each substance has a unique set of properties that

distinguishes it from all other substances •  Types

–  Physical –  Chemical

Property

Section 1.3


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•  Characteristic that can be observed without changing the basic identity of a substance –  Includes color, odor, physical state, melting point,

boiling point, and hardness

Physical Property

Section 1.3


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Concept Check

•  To measure the boiling point of a substance, a liquid must be changed into a gas. Why is boiling point considered a physical property when a gas’ appearance is much different from that of a liquid?


Section 1.3


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Concept Check

•  To measure the boiling point of a substance, a liquid must be changed into a gas. Why is boiling point considered a physical property when a gas’ appearance is much different from that of a liquid?

Although the appearance is different, the substance is still the same. Its chemical identity remains the same irrespective of the physical state.


Section 1.3


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Chemical Property

•  Characteristic that describes the way a substance undergoes or resists change to form a new substance –  Example: Copper objects turn green in air

•  Changes result from the reaction of a substance with one or more other substances –  Decomposition - Change triggered by the presence of

energy


Section 1.3


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Which of the following statements concerning the properties of matter is false? a.  Properties of matter are of two types: physical and chemical. b.  A physical property is a characteristic of matter that can be observed without changing its basic identity. c.  A chemical property describes the way matter undergoes or resists change to form a new substance. d.  One example of the physical property of water is that it can be broken down into hydrogen and oxygen gases.


Section 1.3


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Which of the following statements concerning the properties of matter is false? a.  Properties of matter are of two types: physical and chemical. b.  A physical property is a characteristic of matter that can be observed without changing its basic identity. c.  A chemical property describes the way matter undergoes or resists change to form a new substance. d.  One example of the physical property of water is that it can be broken down into hydrogen and oxygen gases.


Section 1.3


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Figure 1.3 - Chemical Property of Copper


Section 1.3


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Exercise

•  Classify each of the following as a physical or chemical property.

a.  Iron metal rusts in an atmosphere of moist air.

b.  Mercury metal is a liquid at room temperature.

c.  Nickel metal dissolves in acid to produce a light green solution.


Section 1.3


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Exercise

•  Classify each of the following as a physical or chemical property.

a.  Iron metal rusts in an atmosphere of moist air.

Chemical property b.  Mercury metal is a liquid at room temperature.

Physical property c.  Nickel metal dissolves in acid to produce a light

green solution. Chemical property


Section 1.4

Changes in Matter

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•  Process in which a substance changes its physical appearance but not its chemical composition

•  Does not lead to the formation of a new substance –  Example: Boiling or freezing water

Physical Change

Section 1.4

Changes in Matter

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•  Process in which chemical composition of a substance changes

•  Involves conversion of material(s) into one or more new substances –  Example: Rusting of iron objects left exposed to moist

air

Chemical Change

Section 1.4

Changes in Matter

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Use of the Term Physical

Section 1.4

Changes in Matter

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Use of the Term Chemical

Section 1.4

Changes in Matter

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Concept Check

•  Which one of the following is an example of a chemical change?

a.  Pulverizing (crushing) rock salt b.  Burning of wood c.  Dissolving of sugar in water d.  Melting a popsicle on a warm summer day


Section 1.4

Changes in Matter

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Concept Check

•  Which one of the following is an example of a chemical change?

a.  Pulverizing (crushing) rock salt b.  Burning of wood c.  Dissolving of sugar in water d.  Melting a popsicle on a warm summer day


Section 1.5

Pure Substances and Mixtures

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•  Pure substance: Single kind of matter that cannot be separated into other kinds of matter by any physical means –  Example: Water or sucrose

•  Mixture: Physical combination of two or more pure substances –  Each substance retains its own chemical identity –  Example: Salt water

Pure Substances Versus Mixtures

Section 1.5


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Mixtures

•  Have variable composition •  Heterogeneous mixture: Contains visibly

different phases, each of which has different properties

•  Homogeneous mixture: Contains only one visibly distinct phase, which has uniform properties throughout


Section 1.5


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Figure 1.6 - Pure Substances and Mixtures


Section 1.5


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Concept Check

•  Which of the following is a homogeneous mixture?

a.  Pure water b.  Gasoline c.  Jar of jelly beans d.  Soil e.  Copper metal


Section 1.5


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Concept Check

•  Which of the following is a homogeneous mixture?

a.  Pure water b.  Gasoline c.  Jar of jelly beans d.  Soil e.  Copper metal


Section 1.5


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Which of the following contain only pure substances? a.  Oxygen, tap water, glass of tea b.  Oxygen, glucose (a simple sugar), silver c.  Glucose, chocolate chip cookies, wood d.  Gasoline, dirt, rocks


Section 1.5


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Which of the following contain only pure substances? a.  Oxygen, tap water, glass of tea b.  Oxygen, glucose (a simple sugar), silver c.  Glucose, chocolate chip cookies, wood d.  Gasoline, dirt, rocks


Section 1.6

Elements and Compounds

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•  Pure substance that cannot be broken down into simpler pure substances by chemical means such as a chemical reaction, an electric current, heat, or a beam of light –  Example: Gold, silver, copper

Element

Section 1.6


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•  Pure substance that can be broken down into two or more simpler pure substances by chemical means –  Example: Water

Compound

Section 1.6


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Figure 1.7 - A Pure Substance can be an Element or a Compound

Section 1.6


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Distinguishing Between Compounds and Mixtures

Compounds •  Have properties distinctly

different from those of the substances that combined to form the compound

Mixtures •  Components retain their

individual properties


Section 1.6


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Distinguishing Between Compounds and Mixtures

Compounds •  Have a definite chemical

composition •  Components cannot be

separated by physical methods –  Chemical methods are

required

Mixtures •  Have a variable chemical

composition •  Physical methods are

sufficient to separate the components


Section 1.6


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Figure 1.8 - Classifying a Sample of Matter


Section 1.6


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•  Does the sample of matter have the same properties throughout?

•  Are two or more different substances present? •  Can the pure substance be broken down into

simpler substances?

Questions Asked to Classify a Sample of Matter

Section 1.6


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The difference between an element and a compound is: a.  an element is a pure substance, whereas a compound is not. b.  an element can be broken into simpler constituents by physical means, whereas a compound can not. c.  an element can be broken down into a simpler substance by chemical means, whereas a compound can not. d.  an element cannot be broken down into simpler substances by chemical means, whereas a compound can.


Section 1.6


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The difference between an element and a compound is: a.  an element is a pure substance, whereas a compound is not. b.  an element can be broken into simpler constituents by physical means, whereas a compound can not. c.  an element can be broken down into a simpler substance by chemical means, whereas a compound can not. d.  an element cannot be broken down into simpler substances by chemical means, whereas a compound can.


Section 1.7

Discovery and Abundance of the Elements

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•  118 known elements –  88 of the elements occur naturally –  30 of the elements have been synthesized

Section 1.7


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Figure 1.10 - Abundance of Elements (in Atom Percent) in the Universe

Section 1.7


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Figure 1.10 - Abundance of Elements (in Atom Percent) in the Earth’s Crust

Section 1.7


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Which two elements dominate the earth’s crust and which one element dominates the universe? a.  Earth’s crust: oxygen and silicon; universe: hydrogen b.  Earth’s crust: oxygen and silicon; universe: nitrogen c.  Earth’s crust: oxygen and nitrogen; universe: hydrogen d.  Earth’s crust: oxygen and silicon; universe: nitrogen


Section 1.7


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Which two elements dominate the earth’s crust and which one element dominates the universe? a.  Earth’s crust: oxygen and silicon; universe: hydrogen b.  Earth’s crust: oxygen and silicon; universe: nitrogen c.  Earth’s crust: oxygen and nitrogen; universe: hydrogen d.  Earth’s crust: oxygen and silicon; universe: nitrogen


Section 1.8

Names and Chemical Symbols of the Elements

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•  One- or two-letter designation for an element derived from the element’s name –  Two letter symbols can be the first two letters of the

element’s name –  First letter of a chemical symbol is always capitalized

and the second is not •  H – Hydrogen •  Ba – Barium •  Co – Cobalt •  Pb – Lead •  Ag – Silver

Chemical Symbol

Section 1.8


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•  Some elements have symbols that were derived from non-English names –  Ag – Silver –  Au – Gold –  Fe – Iron –  Pb – Lead –  Cu – Copper

Chemical Symbol

Section 1.8


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Chemical symbols consist of: a.  the first letter of the element’s name always in lower case. b.  one- or two-letters derived from the element’s name with both letters always capitalized. c.  the first two letters of the element’s name with both letters capitalized. d.  one- or two-letters derived from the element’s name with the first letter capitalized and the second in lower case.


Section 1.8


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Chemical symbols consist of: a.  the first letter of the element’s name always in lower case. b.  one- or two-letters derived from the element’s name with both letters always capitalized. c.  the first two letters of the element’s name with both letters capitalized. d.  one- or two-letters derived from the element’s name with the first letter capitalized and the second in lower case.


Section 1.9

Atoms and Molecules

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•  Smallest particle of an element that can exist and still have the properties of the element

•  Limit of chemical subdivision –  254 million atoms arranged in a straight line would

extend a distance of approximately 1 inch

Atom

Section 1.9

Atoms and Molecules

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•  Group of two or more atoms that functions as a unit because the atoms are tightly bound together

•  Behaves as a single, distinct particle •  Limit of physical subdivision •  Diatomic molecule: Contains two atoms •  Triatomic molecule: Contains three atoms

Molecule

Section 1.9

Atoms and Molecules

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•  All atoms present are of the same kind •  Substance containing homoatomic molecules

must be an element

Homoatomic Molecule

Section 1.9

Atoms and Molecules

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•  Two or more kinds of atoms are present •  Substances containing heteroatomic molecules

must be compounds

Heteroatomic Molecule

Section 1.9

Atoms and Molecules

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Figure 1.13 - Heteroatomic Molecules

Section 1.9

Atoms and Molecules

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Concept Check

•  Classify XeF4 as:

§  diatomic, triatomic, etc.

§  homoatomic or heteroatomic

§  element or compound


Section 1.9

Atoms and Molecules

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Concept Check

•  Classify XeF4 as:

§  diatomic, triatomic, etc.

pentatomic §  homoatomic or heteroatomic

heteroatomic §  element or compound

compound


Section 1.9

Atoms and Molecules

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Which of the following statements is true? a.  The smallest particle of an element that can exist and still have properties of the element is called an atom. b.  A group of two or more atoms that function as a unit form a molecule. c.  Some classifications of molecules are: diatomic, homoatomic, and heteroatomic. d.  All of these.


Section 1.9

Atoms and Molecules

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Which of the following statements is true? a.  The smallest particle of an element that can exist and still have properties of the element is called an atom. b.  A group of two or more atoms that function as a unit form a molecule. c.  Some classifications of molecules are: diatomic, homoatomic, and heteroatomic. d.  All of these.


Section 1.10

Chemical Formulas

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•  Notation made up of the chemical symbols of: –  Elements present in a compound –  Numerical subscripts

•  Indicate the number of atoms of each element present in a molecule of the compound

•  Examples –  H2O - Two atoms of hydrogen, one atom of oxygen –  Ca3(PO4)2 - Three atoms of calcium, two atoms of

phosphorus, eight atoms of oxygen

Section 1.10

Chemical Formulas

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Exercise

•  For each of the following chemical formulas, determine how many atoms of each element are present:

a.  H2SO4

b.  Fe2(CO3)3


Section 1.10

Chemical Formulas

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Exercise

•  For each of the following chemical formulas, determine how many atoms of each element are present:

a.  H2SO4

two hydrogen; one sulfur; four oxygen b.  Fe2(CO3)3 two iron; three carbon; nine oxygen


Section 1.10

Chemical Formulas

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Chemical formulas consist of: a.  symbols of each element in a compound with all letters capitalized. b.  symbols of each element in a compound with all letters in lower case. c.  symbols of each element in a compound with numerical subscripts to indicate the number of atoms of each element in the compound. d.  symbols of each element in a compound.


Section 1.10

Chemical Formulas

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Chemical formulas consist of: a.  symbols of each element in a compound with all letters capitalized. b.  symbols of each element in a compound with all letters in lower case. c.  symbols of each element in a compound with numerical subscripts to indicate the number of atoms of each element in the compound. d.  symbols of each element in a compound.


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Chapter 1

Concept Question 1

An electrical current is applied to 50 mL of water. After a period of time, there is nothing left in the container because: a.  a physical change occurs resulting in the formation of a gas. Since water is a heterogeneous mixture, its components are also changed to gas. b.  a physical change, evaporation, occurs and as there is no residue, water is a pure substance. c.  a chemical change takes place converting water to its elements, hydrogen and oxygen. No residue is left because water is a pure compound. d.  a chemical change takes place, but water is a heterogeneous mixture and its components are converted to gases.


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Chapter 1

Concept Question 1

An electrical current is applied to 50 mL of water. After a period of time, there is nothing left in the container because: a.  a physical change occurs resulting in the formation of a gas. Since water is a heterogeneous mixture, its components are also changed to gas. b.  a physical change, evaporation, occurs and as there is no residue, water is a pure substance. c.  a chemical change takes place converting water to its elements, hydrogen and oxygen. No residue is left because water is a pure compound. d.  a chemical change takes place, but water is a heterogeneous mixture and its components are converted to gases.


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Chapter 1

Concept Question 2

You are given two cylinders, each containing a gas. You are requested to test the flammability of each gas, and you discover that one gas is very flammable, but the other gas extinguishes the flame. The two gases are _____ and _____ and are classified as a _____ and _____, respectively. a.  hydrogen; methane; homoatomic molecule; heteroatomic molecule b.  hydrogen; carbon dioxide; diatomic molecule; heteroatomic molecule c.  neon; carbon dioxide; element; diatomic molecule d.  hydrogen; oxygen; element; element


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Chapter 1

Concept Question 2

You are given two cylinders, each containing a gas. You are requested to test the flammability of each gas, and you discover that one gas is very flammable, but the other gas extinguishes the flame. The two gases are _____ and _____ and are classified as a _____ and _____, respectively. a.  hydrogen; methane; homoatomic molecule; heteroatomic molecule b.  hydrogen; carbon dioxide; diatomic molecule; heteroatomic molecule c.  neon; carbon dioxide; element; diatomic molecule d.  hydrogen; oxygen; element; element


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Basic Concepts About Matter - · PDF file1.4 Changes in matter ... composition, and transformations of matter Chemistry . Chemistry: The Study of Matter Return to TOC Section 1.1