Chemistry Module 1 - Solids Liquids and Gases
Welcome to the ScienceWeb's Chemistry Modules. These modules are a series of student activities and readings that will help your child understand chemistry. Each Module will be covered in class, however they are also recommended for reading at home. Lets begin with this reading about Matter!
|Solids, Liquids, Gases and Plasma Oh My!|
Properties of Matter
Kinds of Matter
Changes in Matter
Matter is the "stuff" that makes up everything in the universe. Books, flowers, basketballs, wood, and gold ear rings as well as everything else is made up of matter. All matter takes up space and has mass, yet matter can exist in different states.
All matter has properties that can be described. Matter may be any color, or have no color at all. It may be hard, soft, brittle, malleable, conductive or flammable. Matter may have texture and a shape. Each specific substance has its own combination of properties that can be used to identify the substance. The properties of various types of matter leads to its many uses. Gold for example is malleable yet strong allowing us to use it to make jewelry from it. Gold is also very conductive and is used in the computer industry to allow the passage of electricity through the computer. Investigating the various properties of matter is the job of chemists. Chemistry is the study of the properties of matter and how matter changes.
All matter is made of about 100 basic building blocks called elements. An element is a substance that cannot be broken down into any other substances by chemical or physical means. Elements are called the building blocks of matter because all matter is composed of elements. Each element is made up of tiny particles called atoms.
Elements can exist in an uncombined or a combined form. Most oxygen present in the air is not combined with another element. In nature, however, most elements are found combined with one or more elements to form a compound. A compound is a substance made of two or more elements chemically combined.
Most matter that you find in the environment occurs as mixtures. A mixture is made from two or more substances, elements, compounds or both, that are together in the same place but not chemically combined into a new substance.
A change that alters the form or appearance of a material but does not make the material into another substance is called a physical change. Examples of a physical change include the cutting of paper, bending wire into new shapes or changes of states. All matter is found as a solid, liquid or gas on earth. Plasma, the fourth state of matter is found throughout the universe in stars.
Some substance change state with just a small amount of heating or cooling, while other forms of matter require intense heat or extreme cold to cause a change in state. Investigating how matter changes state is one way chemists study matter.
A change in matter that produces new substances is called a chemical change. The new substances are made from the same elements as the original substances, but the atoms are rearranged in new combinations to form the new substances.
The world around you is full of substances that can be classified as solids, liquids and gases. Those substance may be elements, compounds or mixtures. Copper is and element. Air is a mixture of gases. Water is a compound that you have seen as both a solid or a liquid. The states of matter are not defined by what they are made of, but mainly by whether or not they hold their volume and shape.
A solid is one form of matter. Substances that are in the solid state have a definite volume and a definite shape. The particles of a solid are packed closely together and each particle is tightly fixed in one position. This makes it hard to separate them. There are two types of solids. They are called crystalline solids and amorphous solids. Crystalline solids are made up of particles that are called crystals that form a regular and repeating pattern throughout the solid. Crystalline solids melt at a distinct temperature called the melting point of the solid. The second kind of solid is called an amorphous solid. Amorphous solids do not have a crystalline structure nor do they have a distinct melting point. Plastics rubber and glass are some examples of an amorphous solid. As they are heated they become softer and softer until they finally melt.
Unlike a solid, a liquid has no shape of its own. Instead a liquid takes on the shape of its container. Without a container a liquid would spread out into a wide shallow puddle. Liquids, like solids, do not easily expand or compress. The particles of a liquid are packed almost as closely as a solid. However, the particles in a liquid move around one another freely. Because its particles are free to move, a liquid has no definite shape. However, it does have a definite volume.. Because particles in a liquid are free to move around one another, a liquid can flow from place to place. Some liquids flow more easily than others. The resistance of a liquid to flow is called viscosity. Liquids with high viscosity flow slowly.
Unlike solids and liquids, a gas can change volume very easily. The volume and shape of a gas is the volume and shape of its container. Gas particles spread apart, filling all the space available to them. This a gas has neither a definite shape or a definite volume,
Plasma is the fourth state of matter. Plasma is the matter found within our sun, the stars and nebula found in space. The most common form of matter in the universe is plasma . Plasma is a gaslike mixture of positively and negatively charged particles. Plasma consists of a nucleus containing protons and neutrons, the electrons normally common in solids, liquids and gases have been stripped away from the nucleus. In a plasma, matter is compressed so tightly that enormous heat is given off.
What accounts for the characteristics of solids, liquids, gases and plasmas? Tiny particles in constant motion make up all matter. This idea is called the kinetic theory of matter. The particles in a solid are held close together by forces between them. This is why a solid cannot be squeezed into a smaller space. Because the particles lack enough energy to move around easily explains why a solid holds its shape. The kinetic theory of matter also explains the properties of liquids. Because a liquid cannot be squeezed, its particles must also be close together, like those of a solid. However, they have enough kinetic energy in its particles to move over and around each other. This movement of its particles lets a liquid flow and take the shape of its container. According to the kinetic theory of matter, the particles of a gas have enough energy to separate completely from one another. This again explains why a gas takes the shape and volume of its container.
This page was last updated: 11/03/02