Presentation on theme: "The study of the composition, structure, and properties of matter and the changes it undergoes. considers behaviors of materials as well. What is chemistry?"— Presentation transcript:
the study of the composition, structure, and properties of matter and the changes it undergoes. considers behaviors of materials as well. What is chemistry? Branches of Chemistry 1.Organic chemistry: studies compounds composed of carbon. 2.Inorganic chemistry: studies compounds that do not contain carbon. 3.Physical chemistry: studies the relationship between energy and matter. 4.Analytical chemistry: identifies the components and make-up of materials. 5.Biochemistry: studies the substances and processes involved in living things. 6.Theoretical chemistry: utilizes computers to design and predict the properties of new substances. Chapters 1 & 2: Intro to Chemistry & Matter and Change
Scientific method Most scientific advances result from carefully planned investigation. Scientific method Observing collecting data measuring Formulating Hypotheses analyzing data predicting Testing experimenting collecting data If data does not support hypothesis Theorizing constructing models predicting Publish Results communicating
Scientific method 1. 1. Observing Making measurements and/or collecting data. Data can be either qualitative (descriptive/words) or quantitative (numerical). 2. 2. Formulating Hypotheses A testable statement that serves as the basis for making predictions. 3. 3. Testing Hypotheses Experiments are performed that provide data to support or refute a hypothesis. 4. 4. Theorizing When predictions of the hypothesis are successful, scientists use models (explanations of how phenomena occur and how events are related). Theories: a generalization that explains body of facts and phenomena.
Change of State SolidLiquidGas freezing melting boiling Condensation solid: matter with a definite shape and definite volume. liquid: matter with a definite volume but an indefinite shape. gas: matter without a definite shape or volume. Solid, Liquid, Gas
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Matter and Its Properties all matter takes up space (has volume) and has mass. mass: a measure of the amount of matter. Objects that have a large amount of matter will have a large mass, and objects with a small amount of matter will have a small mass. Basic Building Blocks of Matter all matter is made up of atoms and/or molecules. atom: the smallest unit of an element that maintains the properties of that element. element: a pure substance made of only one kind of atom. molecule: a substance that is comprised of two or more elements that are chemically bonded. compound: a substance that is comprised of two or more different elements that are chemically bonded.
Properties and Changes in Matter What is a property? a characteristic that defines an entire group of substances. 1.Extensive property: depend on the amount of matter present. ex: volume, mass, energy 2.Intensive property: do not depend on the amount of matter present. ex: melting point (freezing point), boiling point, density, conductivity Substances can also be further classified: physical properties andchemical properties. 1.Physical properties: a characteristic that can be observed or measured without changing the identity of the substance. ex: melting point, boiling point A change in a substance that does not involve a change in the identity of a substance is called a physical change. ex: grinding, cutting, changes of state (melting & boiling) Changes in Matter Video
Chemical Properties and Chemical Changes 2. chemical properties: pertains to a substance’s ability to undergo changes that transform it into different substances. ex: combustibility, rusting, tarnishing chemical change: a change in which one or more substances are converted into different substances. “chemical reaction” REACTANTSPRODUCTS Gummi Bear Rxn
Classification of Matter all matter can be classified as either a pure substance or a mixture. all matter can be classified as either a pure substance or a mixture. pure substances elements & compounds pure substances elements & compounds mixtures a blend of two or more kinds of matter, each of which retains its own identity and properties. mixtures a blend of two or more kinds of matter, each of which retains its own identity and properties. 1.Homogeneous mixtures: uniform in composition.Homogeneous mixtures: uniform in composition. ex: salt water solution 2.Heterogeneous mixtures: not uniform in composition.Heterogeneous mixtures: not uniform in composition. ex: muddy water Mixtures can be separated physically. 1.FiltrationFiltration 2.Decanting (“pouring off”)Decanting (“pouring off”) 3.Paper chromatographyPaper chromatography 4.CentrifugationCentrifugation Pure substances differ from mixtures in the following ways: 1.Every sample of a pure substance has exactly the same characteristic properties.Every sample of a pure substance has exactly the same characteristic properties. 2.Every sample of a given pure substance has exactly the sameEvery sample of a given pure substance has exactly the same composition. Separating Mixture Separating Ink
ELEMENTS Introduction to the Periodic Table the elements are organized based on similar chemical properties. vertical columns of the periodic table are called groups. horizontal rows of elements are called periods. Types of Elements 1. Metals: have luster (shiny) and are good conductors of heat and electricity. Most metals are solids at room temp. Metals are malleable: they are capable of being hammered or rolled into thin sheets. Metals are ductile: they can be drawn into a fine wire. (due to the high tensile strength of metals)
2. Nonmetals: elements that are poor conductors of heat and electricity. many nonmetals are gases at room temperature (some are solids). solid nonmetals are brittle. rarely have metallic luster (dull appearance). usually do not react with acids. 3. Metalloids: elements that have some characteristics of metals and some characteristics of nonmetals.