Everything in the Universe can be classified as either matter or energy! So what is matter? Define matter: Matter is anything that has mass and occupies a volume. Matter is the “stuff” the Universe is made of A Kaboom Key Concept! 1. All matter is composed of very tiny particlesThis is the first statement of the Particle Model of Matter. 2. Particles are in constant motion. 3. Particles have spaces between them. The spaces are much larger than the particles themselves. 4. Particles are attracted to each other by electrostatic forces. 2
Particles are in constant motion . . .The energy of the particles in matter determines particle motion andaffects the how far apart the particles are from each other.We can think of particle energy as TEMPERATURE. As temperature increases , the average energy of the particles increasesThe temperature determines the phase or state of the matter 3
Physical changes . . .change a substance WITHOUTchanging its chemical makeup.After a physical change, you still havethe same substance, it is just in adifferent form.Examples: boiling, freezing, melting, condensation dissolving split, crack, crush etc 12
Physical properties ..are qualities which can be observed withoutchanging the substance’s composition.For example: boiling point, freezing point, melting point color hardness density malleability, ductility solubility conductivity 13
Chemical changes Substances are broken down in chemical reactions and new substances are made.Example - Burning hydrogen(H2) with oxygen (O2) givesH2O. 14
Chemical Properties describe the howsubstances react chemically. For example: Metals react in acid to produce H2 gas Zn (s) + HCl (aq) H2 (g) + ZnCl2 (aq) DJY - Chemistry I 15
In a CHEMICAL CHANGE, the composition of theoriginal substance(s) is altered.The process of chemical change is described as achemical reaction. chemical changeREACTANTS PRODUCTSDifferent substances are present at the end of thechemical change. The atoms in the reactants arerearranged to make new and different products. 16
Signs of a Chemical Change Color change Heat Light Gas Produced (not from boiling!) Precipitate – a solid formed by mixing two liquids together 17
Physical vs. Chemical Properties Examples melting point flammable density magnetic tarnishes in air 18
Physical vs. Chemical Properties Examples melting point physical flammable chemical density physical magnetic physical tarnishes in air chemical 19
Physical vs. Chemical Changes Examples: rusting iron dissolving in water burning wood melting ice grinding spices 20
Physical vs. Chemical Changes Examples: rusting iron chemical dissolving in water physical burning wood chemical melting ice physical grinding spices physical 21
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