Pure Substance. A sample of matter, either a single element or a single compound, that has definite chemical and physical properties. Element. A pure substance that cannot be broken down into other substances by chemical or physical means.
Elements cannot be broken down into anything simpler physically or chemically. Compounds: are pure substances that are made up of more than l type of atom and can be broken down or decomposed into its individual elements by chemical methods, but cannot be separated by physical methods.
<span>he accelerates when he runs away from home plate. as he reaches each base, the player accelerates by changing direction. he accelerates again when slowing down after reaching home plate.</span>
