Chapter 3: Matter—Properties and Changes

Chapter 3: Matter—Properties and Changes

CHEMISTRY Matter and Change

Section 3.1 Properties of Matter

Section 3.2 Changes in Matter

Section 3.3 Mixtures of Matter

Section 3.4 Elements and Compounds

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CHAPTER

3 Table Of Contents

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• Identify the characteristics of a substance.

density: a ratio that compares the mass of an object to its volume

• Distinguish between physical and chemical properties.

• Differentiate among the physical states of matter.

SECTION3.1

Properties of Matter

states of matter

solid

liquid

gas

vapor

Most common substances exist as solids, liquids, and gases, which have diverse physical and chemical properties.

physical property

extensive property

intensive property

chemical property

SECTION3.1

Properties of Matter

• Matter is anything that has mass and takes up space.

• Matter is everything around us.

• Matter with a uniform and unchanging composition is a substance.

SECTION3.1

Properties of Matter

Substances

• The physical forms of matter, either solid, liquid, or gas, are called the states of matter.

• Solids are a form of matter that have their own definite shape and volume.

• Liquids are a form of matter that have a definite volume but take the shape of the container.

SECTION3.1

Properties of Matter

States of Matter

• Gases have no definite shape or volume. They expand to fill their container.

• Vapor refers to the *

SECTION3.1

Properties of Matter

States of Matter (cont.)

• A physical property is a *

SECTION3.1

Properties of Matter

Physical Properties of Matter

• Extensive properties, such as mass, length, and volume, are *

• Intensive properties, such as density, are dependent * .

SECTION3.1

Properties of Matter

Physical Properties of Matter (cont.)

• * is called a chemical property.

– Iron forming rust

– Copper turning green in the air

SECTION3.1

Properties of Matter

Chemical Properties of Matter

• A substance can change form–an important concept in chemistry.

• Both physical and chemical properties can change with specific environmental conditions, such as temperature and pressure.

SECTION3.1

Properties of Matter

Observing Properties of Matter

• Define physical change and list several common physical changes.

observation: orderly, direct information gathering about a phenomenon

• Define chemical change and list several indications that a chemical change has taken place.

• Apply the law of conservation of mass to chemical reactions.

SECTION3.2

Changes in Matter

Matter can undergo physical and chemical changes.

physical change

phase change

chemical change

law of conservation of mass

SECTION3.2

Changes in Matter

• * is known as a physical change.

• A phase change is a transition of matter from one state to another.

• Boiling, freezing, melting, and condensing all describe phase changes in chemistry.

SECTION3.2

Changes in Matter

Physical Changes

• * is called a chemical change.

• Decomposing, rusting, exploding, burning, or oxidizing are all terms that describe chemical changes.

SECTION3.2

Changes in Matter

Chemical Changes

• The law of conservation of mass states that *.

• The mass of the reactants equals the mass of the products.

massreactants = massproducts

SECTION3.2

Changes in Matter

Conservation of Mass

• Contrast mixtures and substances.

substance: a form of matter that has a uniform and unchanging composition; also known as a pure substance

• Classify mixtures as homogeneous or heterogeneous.

• List and describe several techniques used to separate mixtures.

SECTION3.3

Mixtures of Matter

Most everyday matter occurs as mixtures—combinations of two or more substances.

mixture

heterogeneous mixture

homogeneous mixture

solution

filtration

distillation

crystallization

sublimation

chromatography

SECTION3.3

Mixtures of Matter

• A mixture is a *.

• A homogenous mixture is a mixture where the *.

SECTION3.3

Mixtures of Matter

Mixtures

• Homogeneous mixtures are also called solutions.

• A heterogeneous mixture is a mixture where the individual substances remain distinct.

SECTION3.3

Mixtures of Matter

Mixtures (cont.)

SECTION3.3

Mixtures of Matter

Mixtures (cont.)

• Filtration is a technique that *

• Distillation is a separation technique *

• Crystallization is a separation technique for *

SECTION3.3

Mixtures of Matter

Separating Mixtures

• Sublimation is the process of a solid changing directly to a gas, which can be used to separate mixtures of solids when one sublimates and the other does not.

• Chromatography is a *

SECTION3.3

Mixtures of Matter

Separating Mixtures (cont.)

• Distinguish between elements and compounds.

proportion: the relation of one part to another or to the whole with respect to quantity

• Describe the organization of elements in the periodic table.

• Explain how all compounds obey the laws of definite and multiple proportions.

SECTION3.4

Elements and Compounds

A compound is a combination of two or more elements.

element

periodic table

compound

law of definite proportions

percent by mass

law of multiple proportions

SECTION3.4

Elements and Compounds

• An element is a *

• 92 elements occur naturally on Earth.

• Each element has a unique name and a one, two, or three-letter symbol.

• The periodic table organizes the *

SECTION3.4

Elements and Compounds

Elements

• The periodic table organizes *

• Elements in the same group have similar chemical and physical properties.

• The table is called periodic because the pattern of similar properties repeats from period to period.

SECTION3.4

Elements and Compounds

Elements (cont.)

• A compound is a *.

• Most of the matter in the universe exists as compounds.

• Table salt, NaCl, and water, H2O, are compounds.

• Unlike elements, compounds can be broken into smaller components by chemical means.

SECTION3.4

Elements and Compounds

Compounds (cont.)

• Separating a compounds into its elements often requires external energy, such as heat or electricity.

• This figure shows electrolysis of water to form hydrogen and oxygen gas.

SECTION3.4

Elements and Compounds

Compounds (cont.)

• The properties of a compound are different from its component elements.

SECTION3.4

Elements and Compounds

Compounds (cont.)

• The law of definite proportions states that a compound is always composed of the same elements in the same proportion by mass, no matter how large or small the sample.

–Ex. Water is always composed of 2 Hydrogen to 1 Oxygen

SECTION3.4

Elements and Compounds

Law of Definite Proportions

• The relative amounts are expressed as percent by mass, the *.

SECTION3.4

Elements and Compounds

Law of Definite Proportions (cont.)

• This table demonstrates that the percentages of elements in sucrose remain the same despite differences in sample amount.

SECTION3.4

Elements and Compounds

Law of Definite Proportions (cont.)

• The law of multiple proportions states that when different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in whole number ratios.

– Ex. Peroxide, H2O2, and water, H2O.

–Different compounds formed from the same elements.

–Hydrogen mass the same in both compounds but oxygen mass is a 2:1 ratio in peroxide to water.

SECTION3.4

Elements and Compounds

Law of Multiple Proportions

SECTION3.4

Elements and Compounds

Law of Multiple Proportions (cont.)

Key Concepts

• The three common states of matter are solid, liquid, and gas.

• Physical properties can be observed without altering a substance’s composition.

• Chemical properties describe a substance’s ability to combine with or change into one or more new substances.

• External conditions can affect both physical and chemical properties.

SECTION3.1

Properties of Matter

Study Guide

• A physical change alters the physical properties of a substance without changing its composition.

• A chemical change, also known as a chemical reaction, involves a change in a substance’s composition.

• In a chemical reaction, reactants form products.

• The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction; it is conserved.

massreactants = massproducts

Study Guide

SECTION3.2

Changes in Matter

Key Concepts

• A mixture is a physical blend of two or more pure substances in any proportion.

• Solutions are homogeneous mixtures.

• Mixtures can be separated by physical means. Common separation techniques include filtration, distillation, crystallization, sublimation, and chromatography.

Study Guide

SECTION3.3

Mixtures of Matter

Key Concepts

• Elements cannot be broken down into simpler substances by physical or chemical means.

• Elements are organized in the periodic table of the elements.

• Compounds are chemical combinations of two or more elements and their properties differ from the properties of their component elements.

Study Guide

SECTION3.4

Elements and Compounds

Key Concepts

• The law of definite proportions states that a compound is always composed of the same elements in the same proportions.

• The law of multiple proportions states that if elements form more than one compound, those compounds will have compositions that are whole-number multiples of each other.

SECTION3.4

Elements and Compounds

Study Guide

Key Concepts