Defination of
1)element
2)compound
3)mixtures
1.ELEMENT--An element or chemical element is the simplest form of matter in that it cannot be further broken down using any chemical means. Yes, elements are made up of smaller particles, but you can't take an atom of an element and perform any chemical reaction that will break it apart or join its subunits to make a bigger atom of that element.
2.COMPOUND--
Two types of chemical bonds common in compounds are covalent bonds and ionic bonds.
The elements in any compound are always present in fixed ratios.
Example 1: Pure water is a compound made from two elements - hydrogen and oxygen. The ratio of hydrogen to oxygen in water is always 2:1. Each molecule of water contains two hydrogen atoms bonded to a single oxygen atom.
Example 2: Pure table salt is a compound made from two elements - sodium and chlorine. The ratio of sodium ions to chloride ions in sodium chloride is always 1:1.
Example 3: Pure methane is a compound made from two elements - carbon and hydrogen. The ration of hydrogen to carbon in methane is always 4:1.
Compounds can be decomposed chemically into their constituent elements.
3.MIXTURES--
â— The substances in a mixture can be separated using physical methods such as filtration, freezing, and distillation. â— There is little or no energy change when a mixture forms. â— Mixtures have variable compositions, while compounds have a fixed, definite formula. â— When mixed, individual substances keep their properties in a mixture, while if they form a compound their properties can change. Examples of Common Mixtures: â— Sea water - a mixture of water and various salts. â— Crude oil - a mixture of organic compounds - mainly hydrocarbons. â— Gunpowder - a mixture of potassium nitrate, sulfur and carbon. â— Dry Air - a mixture of nitrogen, oxygen, argon, carbon dioxide, neon and tiny traces of other gases. (Air normally also contains water vapor as part of the mixture.) â— Ink - a mixture of colored dyes which can be separated using chromatography.