2 Unit 4: The Nature of Matter Table of Contents15Unit 4: The Nature of MatterChapter 15: Classification of Matter15.1: Composition of Matter15.2: Properties of Matter
3 Elements 15.1 All substances are built from atoms. Composition of Matter15.1ElementsAll substances are built from atoms.element – Pure Substance- all the atoms in a have the same identityExamples: ?
4 Elements 15.1 About 90 elements are found on Earth. Composition of Matter15.1ElementsAbout 90 elements are found on Earth.More than 20 others have been made in laboratories, but most of these are unstable and exist only for short periods of time.
5 Composition of Matter15.1CompoundsCompound- two or more elements combine to form substances (has a specific chemical composition)Examples?
11 Composition of Matter15.1Homogeneous MixturesHomogeneous mixture two or more gaseous, liquid, or solid substances blended evenly throughout.Examples?
12 Homogeneous Mixtures 15.1 Solution – (AKA- homogeneous mixture) Composition of Matter15.1Homogeneous MixturesSolution –(AKA- homogeneous mixture)Particles cannot be seen with a microscopeWill never settle to the bottom of their container.
13 Composition of Matter15.1Colloidscolloid -Mixture with particles that are larger than those in solutions but not heavy enough to settle out.Not homogeneous or heterogeneousExamples?
14 Composition of Matter15.1Detecting ColloidsTyndall effect- scattering of light by colloidal particles
15 Composition of Matter15.1Suspensionssuspension, which is a heterogeneous mixture containing a liquid in which visible particles settle.Examples?
16 Composition of Matter15.1SuspensionsThe table summarizes the properties of different types of mixtures.
17 Section Check15.1Question 1A _______ is a type of matter with a fixed composition.A. colloidB. mixtureC. substanceD. solution
18 Section Check15.1AnswerThe answer is C. A substance can be either an element or a compound.
19 Question 2 15.1 How many elements are found on Earth? A. 5 B. 10 C. 30 Section Check15.1Question 2How many elements are found on Earth?A. 5B. 10C. 30D. 90
20 Section Check15.1AnswerThe answer is D. About 90 elements are found on Earth, and more than 20 have been made in laboratories.
21 Question 3 15.1 How are compounds different from mixtures? Section Check15.1Question 3How are compounds different from mixtures?
22 Section Check15.1AnswerThe atoms in compounds are combined in fixed proportions and cannot be separated by physical means. A mixture is made of two or more substances that can be easily separated by physical means.
23 Properties of Matter15.2Physical Propertiesphysical property - characteristic of a material that you can observe without changing the identity of the material.Examples: color, shape, size, density, melting point, and boiling point.Item Examples:
29 Chemical Properties and Changes Properties of Matter15.2Chemical Properties and Changeschemical property- characteristic of a substance that indicates whether it can undergo a certain chemical change.Examples?
30 Detecting Chemical Change Properties of Matter15.2Detecting Chemical ChangeIf you leave a pan of chili cooking unattended on the stove for too long, your nose soon tells you that something is wrong.This burnt odor is a clue telling you that a new substance has formed.
31 Properties of Matter15.2The Identity Changeschemical change - A change from one substance to anotherIndications of chemical change:OdorTemperature ChangeFormation of gas/solidColorClick image to view movie
32 The Conservation of Mass Properties of Matter15.2The Conservation of Mass
33 The Conservation of Mass Properties of Matter15.2The Conservation of MassLaw of conservation of mass, the mass of all substances equal the mass of all the substances that remain after the change.no mass is lost during a chemical or physical reaction.
34 Question 1 15.2 Which of the following is a chemical property? Section Check15.2Question 1Which of the following is a chemical property?A. boiling pointB. densityC. flammabilityD. melting point
35 Section Check15.2AnswerThe answer is C. Flammability indicates whether a substance will undergo the chemical change of burning.
36 Section Check15.2Question 2A characteristic of a material that can be observed without changing the identity of the substances that make up the material is a _______.
37 Section Check15.2AnswerThe answer is physical property. Examples of physical properties include color, shape, and density.
38 Section Check15.2Question 3What is the law of conservation of mass?
39 Section Check15.2AnswerAccording to the law of conservation of mass, the mass of all substances that are present before a chemical change equals the mass of all substances that remain after the change.
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