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3.1 Matter and Energy. Kinetic Theory of Matter: All matter is made of atoms Atoms always in motion; hotter = faster, faster = hotter Heavier particles move slower than lighter at the same temperature. States of matter. Solid : particles close together ( still move … vibrate)
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3.1 Matter and Energy • Kinetic Theory of Matter: • All matter is made of atoms • Atoms always in motion; hotter = faster, faster = hotter • Heavier particles move slower than lighter at the same temperature
States of matter • Solid: particles close together (still move … vibrate) • definite Shape • definite Volume • Liquid: particles are close but move freely … slide past each other • no definite Shape (container) • definite Volume • Gas: particles are far apart … take available space • no definite Shape • no definite Volume • Plasma: electrons free from nucleus (ionized); like a gas with an electric charge
States of matter • Phase changes: going from 1 state to another … a physical change … involves energy • Exothermic: gives off heat, becomes colder (heat exits) • condensation: (gas to liquid • solidification: (liquid to solid, also called freezing) • deposition: (gas to solid) • Endothermic: absorbs energy, gets warmer (heat goes into it) • melt: (solid to liquid) • evaporate: (liquid to gas) • sublimate: (solid to gas)
Conservation of Mass • Law of Conservation of Mass: • Law of Conservation of Energy: • mass and energy can not be created or destroyed. They only change form. You have the same mass and energy before a reaction as you would after. • Temperature is not the only way to change state of matter. Pressure can also change state of matter. • As pressure goes up, gas liquid solid • As pressure goes down, solid liquid gas
Phase diagrams • show combinations of temperature and pressures to achieve different phases. • Triple point: temperature and pressure at which the substance can be a solid, liquid and gas all at once. • Lines on graph represent phase changes (as either temperature or pressure change)
Phase diagrams • Shows what happens as add heat. Adding energy doesn’t always change the temperature! • During phase change: temperature doesn’t change because energy is causing molecules to move farther apart. (Flat areas). • When not changing phase: temperature goes up as molecules move faster