Physical vs. Chemical

Physical Properties Rule Physical properties are anything you can touch, taste, smell, see and feel. Physical properties are a description of the item. Examples Water Liquid at room temperature, wet, clear, odorless. Density = 1 (relative to water). Rubbing Alcohol Liquid at room temperature, evaporates easily, wet, clear, strong odor. Density = 0.79 (relative to water).

Chemical Properties Rule Chemical properties include how that substance would react to other chemicals, and what chemicals make up the item. Examples Water Composed of two hydrogens per oxygen in the formula H2O. Non-flammable. Dissolves many other substances. Rubbing Alcohol Composed of three carbons, nine hydrogens and one oxygen in the formula CH3-CH2-OH-CH3. Very flammable. Can dissolve some substances.

Physical Change Rule Physical change will change the description of the substance, but it won't change its chemical formula. A change in states of matter is a physical change. Examples Water Dump it out, evaporate it, pour it in a different shaped container, put marbles in it, wipe it on your face. Rubbing Alcohol Liquid at room temperature, evaporates easily, wet, clear, strong odor. Density = 0.79 (relative to water). Paper Crumple it, write on it, make it into a paper airplane, rip it up.

Chemical Properties Rule Chemical properties are reactions that will change what the substance is. It will not have the same chemical formula after the change. Examples Water Electrically zap it until it turns into hydrogen and oxygen. Dissolve stuff in it that rips apart water molecules Rubbing Alcohol Burn it, separate the chemicals, make it react with another substance. Paper Burn it, dissolve it in acid, digest it.

Practice!