Describing & Classifying Matter
Matter
Matter is anything that has mass and takes up space. Some matter things are wood, plastic, water, air, etc. We classify matter by its properties. Matter can be visible and invisible, liquid or solid. The study of matter and how it changes is called Chemistry.
Determining whether or not matter is a substance is the first step to classifying matter. For example: Sodium Chlorine, or table salt, is a pure substance because it has the same composition no matter how you look at it. (grain, boulder of salt, etc.) However, sea salt is not a pure substance because it is formed when seawater is evaporated, leaving other substances with the salt.
Physical Properties
A physical property is a characteristic that can be observed without changing the matter into another type of matter. An example of a physical property is the melting point or boiling point of something. How it looks (the color, shine, texture, conductor, luster, etc.) is also a physical property. The matter is a physical property as long as it doesn’t change into something else.
Chemical Properties
A chemical property is a characteristic that describes something’s ability to become something else. An example of a physical property is injecting carbon dioxide into water. The water will react to the carbon dioxide and create carbonic acid. Because it became a different substance, the reaction of the water is a chemical property. Flammability is another example of a chemical property.
Atoms
An atom is the basic unit from which all matter is made. All different substances are made up of atoms. Not all atoms have the same structure. An atom has a nucleus, which is positively charged, and negatively charged particles around it, called electrons.
Molecules
When most atoms combine with other atoms, a chemical bond forms between them. Extended structures of combined atoms are called molecules. Molecules are groups of two or more atoms that are held together by chemical bonds. Two atoms of the same element can combine to form a molecule. For example, a Hydrogen molecule is made up of two hydrogen atoms that have chemically combined.
Compounds
A compound is a substance made of two or more elements that are chemically combined in a set ratio. They are represented by a chemical formula that shows the elements in the compound and the ratio of atoms. An example is the chemical formula for carbon dioxide, CO2. The subscript 2 tells us that there are two oxygen atoms. When there is only one atom of an element, there is no number subscript.
Compounds with properties different from those of individual elements happen when elements chemically combine. There can be many different compounds made of different combinations of elements. For example, Ethanol is a compound that contains carbon, hydrogen, and oxygen. It has different properties than those elements pure.
Types of Mixtures
Mixtures are made up of two or more substances that are together in the same place but not chemically bonded. Each substance in a mixture keeps its own properties and is not necessarily combined in a set ratio. Heterogeneous mixtures can be easily separated and are not bonded. Trail mix, for example, is easy to separate by type of food. In homogeneous mixtures, on the other hand, it is difficult or impossible to see the different parts. A cake mix is an example of a homogenous mixture because you cannot separate the things inside. Air cannot be seen and is therefore a homogenous mixture. Distillation, evaporation, filtration, or magnetic attraction can be used to separate their parts according to their properties.
Matter
Matter is anything that has mass and takes up space. Some matter things are wood, plastic, water, air, etc. We classify matter by its properties. Matter can be visible and invisible, liquid or solid. The study of matter and how it changes is called Chemistry.
Determining whether or not matter is a substance is the first step to classifying matter. For example: Sodium Chlorine, or table salt, is a pure substance because it has the same composition no matter how you look at it. (grain, boulder of salt, etc.) However, sea salt is not a pure substance because it is formed when seawater is evaporated, leaving other substances with the salt.
Physical Properties
A physical property is a characteristic that can be observed without changing the matter into another type of matter. An example of a physical property is the melting point or boiling point of something. How it looks (the color, shine, texture, conductor, luster, etc.) is also a physical property. The matter is a physical property as long as it doesn’t change into something else.
Chemical Properties
A chemical property is a characteristic that describes something’s ability to become something else. An example of a physical property is injecting carbon dioxide into water. The water will react to the carbon dioxide and create carbonic acid. Because it became a different substance, the reaction of the water is a chemical property. Flammability is another example of a chemical property.
Atoms
An atom is the basic unit from which all matter is made. All different substances are made up of atoms. Not all atoms have the same structure. An atom has a nucleus, which is positively charged, and negatively charged particles around it, called electrons.
Molecules
When most atoms combine with other atoms, a chemical bond forms between them. Extended structures of combined atoms are called molecules. Molecules are groups of two or more atoms that are held together by chemical bonds. Two atoms of the same element can combine to form a molecule. For example, a Hydrogen molecule is made up of two hydrogen atoms that have chemically combined.
Compounds
A compound is a substance made of two or more elements that are chemically combined in a set ratio. They are represented by a chemical formula that shows the elements in the compound and the ratio of atoms. An example is the chemical formula for carbon dioxide, CO2. The subscript 2 tells us that there are two oxygen atoms. When there is only one atom of an element, there is no number subscript.
Compounds with properties different from those of individual elements happen when elements chemically combine. There can be many different compounds made of different combinations of elements. For example, Ethanol is a compound that contains carbon, hydrogen, and oxygen. It has different properties than those elements pure.
Types of Mixtures
Mixtures are made up of two or more substances that are together in the same place but not chemically bonded. Each substance in a mixture keeps its own properties and is not necessarily combined in a set ratio. Heterogeneous mixtures can be easily separated and are not bonded. Trail mix, for example, is easy to separate by type of food. In homogeneous mixtures, on the other hand, it is difficult or impossible to see the different parts. A cake mix is an example of a homogenous mixture because you cannot separate the things inside. Air cannot be seen and is therefore a homogenous mixture. Distillation, evaporation, filtration, or magnetic attraction can be used to separate their parts according to their properties.
