Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Objectives Describe ways in which chemistry is a part of your daily life. Describe the characteristics of three common states of matter. Describe physical and chemical changes, and give examples of each. Identify the reactants and products in a chemical reaction. List four observations that suggest a chemical change has occurred. Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Working with the Properties and Changes of Matter A Chemical is any substance that has a definite composition. A Chemical Reaction is the process by which one or more substances change to produce one or more new substances. Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Chemical Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Physical States of Matter The States of Matter are the physical forms of matter which are solid, liquid, gas, and plasma. Macroscopic refers to what you can see with the unaided eye. Microscopic refers to what you would see if you could see individual atoms. Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Physical States of Matter, continued Properties of the Physical States Solids have a fixed volume and shape that result from the way their particles are arranged. Liquids have a fixed volume but not a fixed shape. Gases have neither fixed volume nor shape. Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Water in Three States Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Solid, Liquid and Gas Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Changes of Matter Physical Changes are changes in which the identity of a substance does NOT change. Changes of state are physical changes. Chemical Changes occur when the identities of substances change and NEW substances form. Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Changes of Matter, continued Chemical Changes mercury(II) oxide  mercury + oxygen Reactants are the substances are the Left-hand side of the arrow. They are used up in the reaction. Products are the substances are the Right-hand side of the arrow. They are made in the reaction. Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Evidence of a Chemical Change Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Changes of Matter, continued Evidence of a Chemical Change Evidence that a chemical change may be happening generally falls into one of the following categories. the evolution of a gas the formation of a precipitate the release or absorption of energy a change in temperature or the giving off of light energy a color change in the reaction system Section 1 What Is Chemistry? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Objectives Distinguish between different characteristics of matter, including mass, volume, and weight. Identify and use SI units in measurements and calculations. Set up conversion factors, and use them in calculations. Identify and describe physical properties, including density. Identify chemical properties. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Matter Has Mass and Volume Matter is anything that has mass and volume. Volume is the space an object occupies. Mass is the quantity of matter in an object. Devices used for measuring mass in a laboratory are called Balances. Weight is the force produced by gravity acting on a mass. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Comparing Mass and Weight Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Units of Measurement When working with numbers, be careful to distinguish between a quantity and its Unit. Quantity describes something that has magnitude, size, or amount. Unit is a quantity adopted as a standard of measurement. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Units of Measurement, continued Scientist Express Measurements in SI Units Scientists worldwide use a set of units called the Système Internationale d’Unités or SI. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Units of Measurement, continued Scientist Express Measurements in SI Units, continued Base units can be too large or too small for some measurements, so the base units may be modified by attaching prefixes. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts SI (Système Internationale d’Unités ) Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Conversion Factor Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Describing Matter Unit of Measurement, continued Converting One Unit to Another A Conversion Factor is a simple ratio that relates 2 units that express a measurement of the same quantity. example: You can construct conversion factors between kilograms and grams as follows: Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Using Conversion Factors Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Describing Matter Converting Units Sample Problem A Convert L to milliliters. Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Sample Problem A Solution The equality that links the two units is 1000 mL = 1 L. (The prefix milli- represents 1/1000 of a base unit.) The conversion factor needed must cancel liters and leave milliliters. Thus, liters must be on the bottom of the fraction and milliliters must be on the top. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Derived Units Many quantities you can measure need units other than the seven basic SI units. These units are derived by multiplying or dividing the base units. Speed is distance divided by time.The derived unit of speed is meters per second (m/s). A rectangle’s Area is found by multiplying its length (in meters) by its width (also in meters). Its unit is square meters (m 2 ). Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Derived Units, continued Volume is another commonly used derived unit. The volume of a book can be found by multiplying its length, width, and height. The unit of volume is the cubic meter (m 3 ). This unit is too large and inconvenient in most labs. Chemists usually use the liter (L). 1L = 1000 mL = 1000 cm 3 Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Properties of Matter Physical Properties A Physical Property of a substance is a characteristic that does not involve a chemical change. Physical properties of a substance can be determined without changing the nature of a substance. Physical properties include texture, state, melting point, and boiling point. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Properties of Matter, continued Density is the Ratio of Mass to Volume The Density of an object is the mass of the object divided by volume of the object. Densities are expressed in derived units such as g/cm 3 or g/mL. Density is calculated as follows: Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Properties of Matter, continued Density of an Object The Density of a substance is the same no mater what the size of the sample is. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Equation for Density Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Properties of Matter, continued Density Can Be Used to Identify Substances Because the Density of a substance is the same for ALL samples, you can use this property to help Identify substances. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Properties of Matter, continued Chemical Properties A Chemical Property a property of matter that describes a substance’s ability to participate in chemical reactions. A chemical property of many substances is that they react with oxygen. example: rusting Some substances break down into new substances when heated. Section 2 Describing Matter Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Comparing Physical and Chemical Properties Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Objectives Distinguish between elements and compounds. Distinguish between pure substances and mixtures. Classify mixtures as homogenous or heterogeneous. Explain the difference between mixtures and compounds. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Classifying Matter An Atom is the smallest unit of an element that maintains the properties of that element. Matter exists in many different forms but there are only 118 types of atoms. Atoms are joined together to make up all the different kinds of matter. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances A Pure Substance is a sample of matter, either a single element or a single compound, that has definite chemical and physical properties. Elements are pure substances that only contain one kind of matter. They cannot be separated or broken down into simpler substances by chemical means. Each element has its own unique set of physical and chemical properties. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Elements are Pure Substances Each elements is represented by a distinct chemical symbol. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Elements as Single Elements or Molecules A Molecule is the smallest unit of a substance that keeps all of the physical and chemical properties of that substance. A molecule usually consists of 2 or more atoms combined in a definite ratio. Diatomic elements exist as two atoms of the same element joined together. H 2, O 2, F 2, Br 2, I 2, N 2, Cl 2 Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Some Elements Have More Than One Form Some elements, such as oxygen, phosphorus, sulfur, and carbon, have many different molecular forms. An Allotrope is one of a number of different molecular forms of an element. The properties of allotropes vary widely. Ex. Carbon; Diamond and Graphite Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Some Elements Have More Than One Form, continued Oxygen exists as allotropes. Oxygen gas (O 2 ) is colorless and odorless. Ozone (O 3 ) is toxic and pale blue. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Compounds are Pure Substances Pure substances that are not elements are Compounds. Compounds are composed of more than one kind of atom. example: Carbon dioxide (CO 2 ) There may be easier ways of preparing them, but compounds can be made from their elements. Compounds can be broken down into their elements, though often with great difficulty. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Compounds are Represented by Formulas Because every molecule of a compound is made up of the same kinds of atoms arranged the same way, a compound has characteristic properties and composition. Compounds can be represented by an abbreviation or Formula. A formula has subscripts which represent the ratio of different atoms in the compound. example: H 2 O has 2 hydrogen atoms and one oxygen atom Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Compounds are Represented by Formulas, continued Molecular formulas give information only about what makes up a compound. example: the molecular formula for aspirin is C 9 H 8 O 4 A Structural Formula shows how the atoms are connected This two-dimensional model does not show the molecule’s true shape. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Compounds are Represented by Formulas, continued A Ball-and-Stick Model shows the distances between atoms and the angles between them in three dimensions. A Space-Filling Model attempts to represent the actual sizes of the atoms and not just their relative positions. A hand-held model can provide more information than models shown on the flat surface of the page. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Pure Substances, continued Compounds are Represented by Formulas, continued These models convey different information about acetylsalicylic acid (aspirin). Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mixtures A Mixture is a combination of two or more substances that are not chemically combined. Air is a mixture of mostly nitrogen and oxygen. All the different gases in air are physically mixed. The proportions of the gases can vary. Water is not a mixture. The H and O atoms are chemically bonded The ratio of H to O atoms is always 2 to 1. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mixtures, continued Mixtures Can Vary in Composition and Properties The proportion of the materials in a mixture can change. The properties of the mixture may vary. An Alloy is a solid mixture. example: An alloy of gold and other metal atoms is stronger than pure gold. 18-karat gold contains 18 grams of gold per 24 grams of alloy. 14-karat gold contains 14 grams of gold per 24 grams of alloy. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Particle Models for Gold and Gold Alloy Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mixtures, continued Homogenous Mixtures A Homogenous Mixture describes something that has uniform structure or composition throughout. examples: gasoline, syrup, and air Because any two samples of a homogenous mixture will have the same proportions of ingredients, homogenous mixtures have the same properties throughout. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mixtures, continued Heterogeneous Mixtures A Heterogeneous Mixture describes something that is composed of dissimilar components. example: A mixture of sand and water is a heterogenous mixture. Any two samples of a heterogeneous mixture will have the different proportions of ingredients. Heterogeneous mixtures have different properties throughout. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Examples of Mixtures Mixtures are either homogenous or heterogeneous. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Types of Mixtures Chapter 1 Section 3 How Is Matter Classified?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Mixtures, continued Distinguishing Mixtures from Compounds The properties of a mixture reflect the properties of the substances it contains. The properties of a compound often are very different from the properties of the elements that make it up. A mixture’s components can be present in varying proportions. A compound has a definite composition in terms of the masses of its elements. Section 3 How Is Matter Classified? Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Classifying Matter Chapter 1 Section 3 How Is Matter Classified?

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu The table and graph below show a relationship of direct proportionality between mass (grams) versus volume (cubic centimeters). Use it to answer questions 9 through 12. Interpreting Graphics Standardized Test Preparation Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 9.Based on information in the table and the graph, what is the relationship between mass and volume of a sample of aluminum? F.no relationship G.a linear relationship H.an inverse relationship I.an exponential relationship Interpreting Graphics Standardized Test Preparation Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 9. Based on information in the table and the graph, what is the relationship between mass and volume of a sample of aluminum? F.no relationship G.a linear relationship H.an inverse relationship I.an exponential relationship Interpreting Graphics Standardized Test Preparation Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 10. From the data provided, what is the density of aluminum? A.0.37 g/cm 3 B.1.0 g/cm 3 C.2.0 g/cm 3 D.2.7 g/cm 3 Interpreting Graphics Standardized Test Preparation Chapter 1

Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 10. From the data provided, what is the density of aluminum? A.0.37 g/cm 3 B.1.0 g/cm 3 C.2.0 g/cm 3 D.2.7 g/cm 3 Interpreting Graphics Standardized Test Preparation Chapter 1