CHAPTER 1: MATTER AND CHANGE. Chemistry 1-2 Mr. Chumbley

Transcription

1 CHAPTER 1: MATTER AND CHANGE Chemistry 1-2 Mr. Chumbley

2 As I take attendance, go through your notebook. Update the Table of Contents, and number any of the unused reference pages with Roman numerals.

3 SECTION 1: CHEMISTRY IS A PHYSICAL SCIENCE EQ: How is chemistry studied and used?

4 WHAT IS CHEMISTRY? For most of human history, the natural sciences were divided into two broad categories: Biological Sciences Physical Sciences However, those divisions began to break down as knowledge increased Chemistry is the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes

5 BRANCHES OF CHEMISTRY As the understanding of matter and its processes increased, different branches of chemistry arose to better describe specific types of chemicals and processes Organic Chemistry Physical Chemistry Biochemistry Inorganic Chemistry Analytical Chemistry Theoretical Chemistry A chemical is any substance that has a definite composition

6 CHEMISTRY APPLICATIONS Basic chemical research is conducted for the purpose of expanding knowledge Applied chemical research is conducted for the purpose of solving a specific problem Technological development involves the production and use of products to improve the quality of life

7 HOMEWORK! Review your notes from today. Use the Cornell Note-Taking Revision Checklist to go back over your notes. On the Left Side respond to the following question: What is one situation in which chemistry has been used to solve a problem (big or small) in my life?

8 SECTION 2: MATTER AND ITS PROPERTIES EQ: How can matter be described?

9 WHAT IS MATTER? It is much easier to identify that things are made up of matter than it is to define matter By looking at the same properties for all matter there are two universal commonalities: Things made of matter take up space (have volume) Things made of matter have mass Mass is a measure of the amount of matter Using these universal characteristics we can define matter Matter is anything that has mass and takes up space

10 ATOMS ARE THE BUILDING BLOCKS OF MATTER While matter exists in many different forms, the most fundamental form is the atom An atom is the smallest unit of an element that maintains the chemical identity of that element An element is a pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom

11 ATOMS ARE THE BUILDING BLOCKS OF MATTER When atoms of different elements chemically combine, molecules of a compound are formed A compound is a substance that can be broken down into simple stable substances, but is made from the atoms of two or more elements that are chemically bonded The smallest unit of a compound is a molecule

12 HOMEWORK Review your notes from today. Use the Cornell Note-Taking Revision Checklist to go back over your notes.

13 As I take attendance, go through your notebook. Update the Table of Contents, and number any of the unused reference pages with Roman numerals.

14 SECTION 2: MATTER AND ITS PROPERTIES EQ: What characteristic properties of matter can be identified?

15 ALL SUBSTANCES HAVE CHARACTERISTIC PROPERTIES The specific characteristics of a substance, either element or compound, are considered its properties Properties can be used to identify individual substances, or an entire group of substances Properties can be one of two types Physical Properties Chemical Properties

16 PHYSICAL PROPERTIES Properties of substances are often used as identifying characteristics Physical properties are characteristics that can be observed or measured without changing the identity of the substance Examples: mass color shape density volume texture boiling point melting point conductivity

17 CHEMICAL PROPERTIES In any situation where a substance could change its identity, chemical properties can be observed Chemical properties relate to a substances ability to undergo changes that transform it into a different substance Examples: reactivity chemical stability flammability toxicity combustibility radioactivity

18 PHYSICAL CHANGES The physical properties of a substance can change, even if the substance does not A physical change is a change in a substance that does not involve a change in the identity of the substance Examples: cutting grinding polishing boiling melting dissolving

19 STATES OF MATTER Matter exists in states of matter that are physical properties When a substance undergoes a change of state, it is a physical change from one state to another While the substance has some new and different physical properties, the chemical identity has not changed

20 STATES OF MATTER State of Matter Definite Shape Definite Volume Solid Yes Yes Liquid No Yes Gas No No As a substance changes from solid to liquid to gas, the atoms or molecules become less organized and have increasing ability to move away from each other A fourth state of matter, plasma, is a hightemperature physical state of matter in which atoms lose most of their electrons

21 CHEMICAL CHANGES A chemical change (or chemical reaction) is a change in which one or more substances are converted into different substances The reactants are the substances that react in a chemical change The products are the substances that are formed by the chemical change

22 SIGNS OF A CHEMICAL CHANGE Production of an odor Change in temperature Change in color Formation of bubbles (gas) Formation of a precipitate (solid) Emission of light

23 ENERGY AND CHANGES IN MATTER In both physical and chemical changes, energy is involved Many different types of energy can be involved The law of conservation of energy says that energy can be absorbed or released, but it is never created nor destroyed

24 HOMEWORK Review your notes from today. Use the Cornell Note-Taking Revision Checklist to go back over your notes.

25 FOLD-IT 4 Create a Fold-It 4 using the following 4 terms: Physical Property Chemical Property Physical Change Chemical Change Take out your unfinished Fold-It from Friday. Complete the last 2 flaps.

26 SECTION 2: MATTER AND ITS PROPERTIES EQ: How can different substances be classified?

27 MATTER CAN BE A PURE SUBSTANCE OR A MIXTURE The variety of forms in which matter can exist is enormous Two major classifications of matter are whether or not it is a pure substance or a mixture Regardless of whether a sample is a pure substance or a mixture, it can be described and classified in terms of its properties

28 PURE SUBSTANCES A pure substance is any form of matter that has a fixed, or definite, composition Pure substances have two defining characteristics: Every sample of a given pure substance has exactly the same characteristic properties. Every sample of a pure substance has exactly the same composition.

29 MIXTURES A mixture is a blend of two or more kinds of matter each of which retains its own identity and properties Another way of describing a mixture is that the matter combines physically, but not chemically Since mixtures do not have a defined composition, the amount of different substances within a sample of a mixture must be specified

30 MIXTURES Mixtures can be described by the uniformity of their composition Homogeneous mixtures (or solutions) are mixtures that are uniform in composition Heterogeneous mixtures are mixtures that are not uniform in composition

31 MIXTURES One of the most important characteristics of a mixture is that it can be physically separated Examples of physical separation: Filtration Vaporization Settling Centrifuge separation Chromatography

32 LABORATORY CHEMICALS AND PURITY Typically, we treat chemicals used in the laboratory as if they were pure Chemicals do have impurity, and depending on the standards and grade desired or used The level of purity is important to know since the level of impurities can affect results

33 HOMEWORK Review your notes from today. Use the Cornell Note-Taking Revision Checklist to go back over your notes.