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Chemistry. Chapter 1 Pages 2 - 35. What is Chemistry. Properties of matter and changes of matter Matter: anything that has mass and takes up space. Chemical. Any substance that has a definite composition Always made of the same stuff in exactly the same proportions
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Chemistry Chapter 1 Pages 2 - 35
What is Chemistry • Properties of matter and changes of matter • Matter: anything that has mass and takes up space
Chemical • Any substance that has a definite composition • Always made of the same stuff in exactly the same proportions • Examples: H2O, NaCl, C12H22O11 • All around us
Chemical reactions • Changes in chemicals • Ex: things growing, food cooking, taking a photo (film) • We use reactions to produce chemicals • Ex: plastics, acids
States of Matter • Solid, Liquid, Gas • What is the difference between ice, water, steam? • Solid • Definite shape, definite volume • Liquid • No definite shape, definite volume • Gas • No definite shape, no definite volume
Physical properties • Properties that can be measured or observed without changing it’s identity • Length, mass, color, odor, density, boiling point, melting point
Changes of Matter • Matter can change • Ice melts, water fogs a mirror, bike spokes rust, red clothes fade, milk sours • 2 types of changes
Physical Changes • A change in which the identity of a substance does not change • Change physical properties • Melting, freezing, dissolving, crushing, boiling
Chemical Changes • Also called a chemical reaction • Things turn into something new • 2 parts of a chemical reaction • Reactants – things that react • Products – things that are produced
Chemical Reaction Reactant + Reactant Product + Product Propane + Oxygen Carbon Dioxide + Water
Evidence of a chemical reaction • 1 of 4 things must happen • A gas is produced • Formation of a precipitate • Release of heat and light • Color change
Classifying Matter • All matter is made of atoms • There are 115 kinds of atoms • Matter is either a pure substance or a mixture
Pure Substance • 2 Types • Can it be separated? • Yes, it is a compound • H2O, NaCl, C6H12O6, H2SO4 • No, it is an element • H, O, Na, Au, Pb
Mixtures • 2 Types • Is it all the same? • Yes, it is a homogeneous mixture • Tap water, air, apple juice • No, it is a heterogeneous mixture • Salt/pepper, orange juice, choc chip cookie