Educational Resources for Chemistry Students

What is Chemistry? Chemistry is part of science and it concerns the composition, properties, reactive characteristics and structure of substances particularly at molecular and atomic levels. There are many aspects of chemistry that students explore when they study the subject in school such as states of matter and the periodic table of elements. The purpose of this article is provide students with a comprehensive guide of chemistry resources.

Measurements/Calculations

Measurements and calculations are very important in the area of Chemistry. What exactly does a measurement consist of? Measurements have both a label or unit (such as pounds or gallons) and a number. The units need to be agreed upon by the people who are making and utilizing them. Measurements are determined through the use of measuring devices such as balances and cylinders. They are made utilizing the metric system in which smaller or larger units than the base unit are factors of 10. Some of the most commonly utilized metric units include: meter to show length; liter to show volume; and gram to show mass. Metric system units can be basic or derived. The use of prefixes relates the two unit types such as kilo which is 1,000 times the basic unit.

Elements, Compounds and Chemical Reactions

Elements, compounds and chemical reactions concern states of matter. An element is a substance that cannot be broken up into a simpler substance. Elements are comprised of atoms which hold the properties of the element but are the smallest particle of it. Examples of elements include silver and gold. Ninety naturally occurring elements exist and scientists created 25 more. A compound is created when you have two or more elements which are chemically joined together such as salt, water or sugar.

A chemical reaction is a process involving reactants (one, two or more substances) that are transformed through a chemical alteration into one or more products which differ from the initial reactants. Rust is created by a chemical reaction when iron and oxygen combine to form a new substance called iron oxide.

Atomic Structure/Molecular Models

Known as the basic building blocks of matter, atoms cannot be broken up by ordinary means. Three different types of particles combine to form atoms including: neutrons, electrons and protons. Both neutrons and protons can be found in the nucleus of an atom while the electrons are found in orbitals surrounding the nucleus. A molecular model represents a molecule. Molecular models can be entirely computational or a real physical object. Molecular bonds can be shown with stick models. Bonds and atoms can be shown using ball and stick models. Finally relative atomic sizes can be shown by space filling models.

Periodic Table of Elements

The periodic table of elements arranges the elements by their atomic numbers in order to place elements that have similar chemical properties in the same column (referred to as groups). The elements are placed in atomic number order from left to right and top to bottom. The elements in a particular column behave relatively the same chemically. When you need information on an element you look at the periodic table.

Matter and Density

Everything that surrounds you is matter. Technically speaking matter is defined as anything taking up space that has mass. Matter can have physical and chemical properties. Physical properties are what matter exhibits without any altering in its identity. An example of a physical property is a melting point which is the temperature when a solid becomes a liquid. Density is another example of a physical property of matter. Density is the amount of mass in a standard volume such as the size of a box. Density is actually a measurement for determining mass per unit volume. When you are figuring out density you need to measure both mass and volume of a substance. The equation for calculating density is: Density=Mass/Volume.

Energy and Thermodynamics

What is thermodynamics? Thermodynamics is part of physics. It involves converting one form of energy to another and how the form affects pressure, volume, temperature, work and mechanical action. There are two laws of thermodynamics. The first law involves the changing of one energy form to another without being able to create or destroy the energy. The second law of thermodynamics is regarding energy exchanges when no energy leaves nor enters the system. The state's potential energy will be less than the energy of the initial state. This is referred to as entropy.

States of Matter

Matter is divided into five main states (also referred to as phases) including: solids, gases, plasmas, liquids and Bose Einstein condensates. When there are special physical forces present, compounds and elements are able to move from one state to another (such as from a liquid to a gas). Things can only move by physical means from one state to another. When you remove or add energy you create a physical change.

Stoichiometry

Stoichiometry is the math involved in Chemistry which is used to determine moles, masses and percents through chemical equations. Symbols in chemistry represent the different chemicals. A chemical equation expresses a chemical process. The equations are often written showing the state in which the substance is in. All chemical equations contain coefficients which show the relative substance amounts that are present.

Acids and Bases

You often encounter acids and bases in both chemistry and every day of your life. The properties of acids and base are opposite so they can neutralize or cancel each other. Substances that increase the concentration of hydrogen ions when they are in water are considered acids. There are both strong and weak acids. Strong acids are ionic compounds which are comprised of hydrogen ions. Substances that decrease hydrogen ion concentration when in water are called bases. In order to decrease the hydrogen ion concentration, strong bases increase the hydroxide ion concentration.

Miscellaneous

Chemistry is an area that can be very fun to learn about and explore. The World Wide Web offers excellent information on the subject area as well as other chemistry options such as games, quizzes and scientific journals.