Chemistry Notes Physical Science = study of matter and energy Chemistry = study of matter Physics = study of matter and its motion Matter = anything that has mass and takes up space Mass is measured in grams(g) or kilograms(kg) Energy = ability to do work

MATTER Physical properties of matter Density – amount of matter in a given volume Ductility – ability to be pulled into a thin wire Malleability – ability to be pressed into a thin sheet Boiling point – temperature at which a substance changes from a liquid to a gas Melting point – temperature at which a substance changes from a solid to a liquid Electrical conductivity – how well a substance allows electricity to flow through it Solubility – ability to dissolve in another substance

Chemical properties describe matter based on its ability to change into a new kind of matter with different properties. Examples of chemical properties: Flamibility Rusting Reactivity to acid Reactivity to water

Physical change – involves the changes that can be observed without changing the identity of substances. (matter looks different, but molecules are the same) Chemical change - a change in matter to produce a new substance. (matter looks different AND molecular structure changes) Physical or Chemical? Crumble paper Rip paper Burn paper Melting ice Newspaper left in sunlight Gatorade mix (Mr. Hughes’ favorite drink) Ripe banana Rusting bicycle

MATTER 3 States of Matter 1.Solid – molecules can vibrate but not move 2.Liquid – molecules can move but stay close together 3.Gas – molecules can move and separate

Kinetic energy – energy of MOTION Kinetic Theory of Matter Particles of matter are in constant random motion Solid at different temperatures Liquid at different temperatures When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space. Mass of the object remains the same, however. Solids, liquids and gases all expand when heat is added. When heat leaves all substances, the molecules vibrate slower. The atoms can get closer which results in the matter contracting. Again, the mass is not changed.

Phase Changes