What is Matter?

Matter is a general term for the substance of which all physical objects consist. Typically, matter includes atoms and other particles which have mass. A common way of defining matter is as anything that has mass and occupies volume.

Three things about Matter that are Studied in Chemistry

• Composition of Matter
• Ways of classifying matter
• Energy Involved in Chemical/ Physical Changes

Composition of Matter

Elements

All matter is composed of atoms.  The number of electrons, protons and electrons, determine the properties of those atoms.  Matter is made up of elements.  Elements are atoms with specific properties.  The main property that defines each element are the number of electrons, proton and neutrons.  An example would be that of hydrogen and helium.  Both of these are elements.  They both have electrons, protons and neutrons but the numbers of each are different.  That difference alone allow for different chemical and physical properties.  An element is defined as matter that is made up of the same kind of atoms.  All sodium atoms have the same physical and chemical properties.  All nickel elements have the same chemical and physical properties, although those properties that define each of the preceding elements are exclusive to those elements alone.  There are 111 recognized elements and they are categorized according to their properties on the Periodic Table. 

Compounds

A compound is composed of two or more elements of different kinds that are combined.  The elements that make up a compound are always composed with the same elements in the same ratios every time.  Glucose is always composed of 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms.  The properties of a compound are different than the elements from which it is made.

Matter is anything that has mass and volume. The mass of matter is measured by the acceleration a body has when a force is applied. The greater the mass, the slower the acceleration for the same force. The volume is determined by the space in three dimensions that it occupies. 

Einstein showed that ultimately all matter is capable of being converted to energy, by the formula 

E = mc^₂

Where E is the energy comprising a piece of matter of mass m, times the c² the speed of light squared (multiplied by itself). As the speed of light is exactly 299,792,458 metres per second or 186,272 miles per second, just a little matter is comprised of a lot of energy. 

Everything we see is comprised of atomic matter, made up of sub-atomic particles, usually a nucleus of protons, neutrons and a cloud of orbiting electrons. When atomic matter is hot enough it ionises (or loses its electrons, usually above about 5,000degrees C) and this causes it to emit the energy of light. The light we see by in this way usually comes from the sun (or other stars at night), either by daylight or by fossil fuels, stored from sunlight captured many millions of years ago. Atomic matter at lower temperatures also can reflect light, absorbing some at specific wavelengths, which determines the colours of the objects we see. 

The WMAP probe, which examined the cosmic microwave background of the universe, enabled us to determine only 4% of the Universe is comprised of ordinary atomic matter, the remainder is either Dark Matter (23%), believed to be weakly interacting massive particles, and Dark Energy (73%) causing an acceleration in the speed with which the universe is expanding. Of the 4% of the composition of the Universe, 0.6% is in luminous stars, the other 3.6% is comprised of clouds of non luminous interstellar dust and gas. 

Atomic matter is found in the form of one of 111 elements, which differ by their nuclear composition. The simplest element, hydrogen, comprises one proton in its nucleus, and one orbiting electron. Helium, the next most simple element generally contains a nucleus of two protons, and two neutrons, with two orbiting electrons. Immediately after the big bang, the universe comprised of 90% hydrogen atoms, 10% helium atoms (by weight 75% hydrogen and 25% helium). Since then all other elements of atomic matter, including most of your body, have been made in the heart of ancient stars. 

The 10 most common elements in the universe by mass are 

ELEMENT.........Parts per million 

Hydrogen........750,000 
Helium.............230,000 
Oxygen...........10,000 
Carbon............5,000 
Neon...............1,300 
Iron.................1,100 
Nitrogen..........1,000 
Silicon..............700 
Magnesium......600 
Sulphur............500 

Antimatter is matter comprised of the anti-particles of ordinary matter. There is very little antimatter in the universe today, but when the universe was formed, 499 parts of every 1000 were particles of antimatter, which was annihilated through contact with particles of ordinary matter, leaving the 2 parts per 1000 as the atomic matter we see today. 

Ways of Classifying Matter

Properties of Matter
The science of chemistry developed from observations made about the nature and behavior of different kinds of matter, which we refer to collectively as the properties of matter.
1. Physical Properties can be observed without the substances changing into other substances. Also, physical properties are properties that describe the appearance or feel of a substance.
        

Examples:

• Color
• Hardness
• Density
• Texture
• Shape
• Size
• Phase

Physical properties of matter are categorized as either Intensive or Extensive.

a. Intensive Properties. Properties of matter that do not depend on the amount of matter.Many of the intensive properties depend on such variables as the temperature and pressure, but the ways in which these properties change with such variables can themselves be regarded as intensive properties.

Examples:

• color (absorption spectrum)
• melting point
• density
• solubility
• acidic or alkaline nature

b. Extensive Properties. Properties of matter that depend on the amount of matter. 

Examples:

• mass
• weight
• volume
• length

2.  Chemical Properties can be observed only when the substance transforms into another      substance.Properties that relate to the ability of a substance to react with other substances, or to transform from one substance to another. The chemical properties of a substance relate to its chemical composition and the way the atoms in the molecules are chemically bonded together. 
        
Examples:

• Iron will rust
• Methane in natural gas will react with oxygen to produce carbon dioxide, water, and heat energy.
• Baking soda will react with vinegar to produce carbon dioxide and water.

Changes in Matter


Matter can undergo either physical or chemical change.


1. Physical Change occurs when a substance changes its appearance without changing its composition. The process of changing from one physical state to another is known as phase change, one type of physical change.


2 .Chemical change  is any process determined by the atomic and molecular composition and structure of the substances involved.

Physical and Chemical Changes

There are several differences between a physical and chemical change in matter or substances.

A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

For example, if a piece of paper is cut up into small pieces it still is paper. This would be a physical change in the shape and size of the paper. If the same piece of paper is burned, it is broken up into different substances that are not paper.

Physical changes can be reversed, chemical changes cannot be reversed with the substance changed back without extraordinary means, if at all. For example, a cup of water can be frozen when cooled and then can be returned to a liquid form when heated.

If one decided to mix sugar into water to make sugar water, this would be a physical change as the water could be left out to evaporate and the sugar crystals would remain. However, if one made a recipe for a cake with flour, water, sugar and other ingredients and baked them together, it would take extraordinary means to separate the various ingredients out to their original form.

When heat is given off in a chemical change or reaction, it is called an exothermic reaction. When heat is absorbed in a chemical change or reaction, it is called an endothermic reaction. The speed at which chemical reactions take place depend on the temperature pressure and how concentrated the substances involved in the chemical reaction are. Sometimes substances called catalysts are used to speed up or help along a chemical reaction. Light is helpful in the processing of film.

 

Film is processed with the assistance of light.	Heat is another factor that facilitates chemical reactions.

 

Physical Change in Water

Water as steam or water vapor. It is formed when water is heated to the boiling point or it evaporates.	Water as a liquid is formed then water vapor is cooled or ice is heated.	Ice is formed when water is cooled to the freezing point.

 

Energy Involved in Chemical or Physical Change

        Energy is the ability to cause change or do work.  Some forms of energy include light, heat, electrical energy and mechanical energy, such as movement.  There are two main forms of energy: potential and kinetic.  Potential energy is energy that is stored, while kinetic energy is energy in use.  Let's look at an example.  In the previous lesson we dropped a weight from the top ledge of the Leaning Tower of Pisa.  As the weight fell it possessed kinetic energy, the energy of movement.  Where did that kinetic energy come from?  It was stored in the weight when the weight was suspended from the ledge of the tower.  We actually put that energy into the weight when we climbed the stairs of the tower carrying the weight with us.  

Signs of Chemical Changes How can you tell whether a change is a chemical change?  If you think you are unfamiliar with chemical changes, think again.		Physical changes are relatively easy to identify.  If only the form of a substance changes, you have observed a physical change. A common physical change occurs when matter changes from one phase to another.  When an ice cube melts for example, it becomes liquid water.  The solid ice and liquid water have the same composition.  The only difference is the form.
Color Changes When you bake a cake, energy is absorbed by the batter as it changes form a runny mix into a cake. You have just witnessed a spectacular chemical change if you have seen the leaves change color in the autumn. As in the case of autumn leaves, a change in color is a clue to indicate a chemical change.
		Energy - Absorbed or Released Another sign of a chemical change is the release or gain of energy by an object.  Many substances absorb energy to undergo a chemical change.  Energy is absorbed during chemical changes involved in cookin g, like baking a cake.
Energy can also be released during a chemical change.  The fireworks that were mentioned above release energy in a form of light that you can see
Odor Changes It only takes one experience with a rotten egg to learn that they smell different that fresh eggs.  When eggs and food spoil, they undergo a chemical change.  The change in odor is a clue to the chemical change.
		Production of Gases or Solids The formation of a gas is  a clue to chemical changes.  The bubbles of gas that you observed  when an antacid is dropped into water is an example of change. Another clue that a chemical change has occurred is the formation of a solid.  A solid that separates out of solution during a chemical change is called a precipitate.
		How do physical and chemical changes differ from each other?  Think about ice for a moment.  After ice melts into liquid water, you can refreeze it into solid ice if the temperature drops.  Freezing and melting are physical changes. The substances produced during chemical changes however cannot easily change back into the original substances.
Chemical vs Physical Change
Chemical ReactionsChemical Changes are also called Chemical Reactions.  Chemical reactions involve combining different substances.  The chemical reaction produces a new substance with new and different physical and chemical properties.  Matter is never destroyed or created in chemical reactions.  The particles of one substance are rearranged to form a new substance. The same number of particles that exist before the reaction exist after the reaction.