Pure Substances and Mixtures
Matter is anything, such as a solid, liquid or gas, that has weight(mass) and occupies space. For anything to occupy space, it must havevolume. Thinking about it, everything on earth has weight and takes up space, and that means everything on earth is matter.
Matter can be classified into two basic categories. Matter is either a mixture or it is a pure substance. We can classify mixtures into two categories - Homogeneous mixtures and heterogeneous mixtures. We can also classify pure substances into two categories - Elements and compounds.
Classification of Matter
Anything that has mass and volume is matter. All of the solids, liquids and gases that you may encounter in your daily life would be classified as some type of matter. You are familiar with the taxonomy of living things from Biology. Now you will learn how scientists classify matter that makes up everything.
Substance - A material with a constant composition. This means that the substance is the same no matter where it is found. NaCl, H2O, Ne, CO2, and O2 are all substances, because their composition will be the same no matter where you find them. All elements and all compounds are defined as substances.
Elements - Elements are substances that are made up of only one type of atom. At this time, there are 113 known elements, most of which are metals. The symbols shown on the periodic table represent the known elements.
Compounds - Compounds are substances that are made up of more than one type of atom. Water, for example, is made up of hydrogen and oxygen atoms. Carbon dioxide is made up of carbon and oxygen atoms. Table salt is made up of sodium and chlorine. Compounds differ from mixtures in that they are chemically combined. Unlike elements, compounds can be decomposed, or broken down by simple chemical reactions.
Phase - A phase is any region of a material that has its own set of properties. In a chocolate chip cookie the dough and the chips have different properties. Therefore they represent separate phases. Pure gold, which is an element, would only contain one phase. Italian dressing would clearly represent several phases, while a solution of salt water may only contain one phase.
Homogeneous Materials - Any material that contains only one phase would be considered homogeneous. Elements like hydrogen, compounds like sugar, and solutions like salt water, are all considered homogeneous because they are uniform. Each region of a sample is identical to all other regions of the same sample.
Mixtures - Mixtures are made up of two or more substances that are physically combined. The specific composition will vary from sample to sample. Some mixtures are so well blended that they are considered homogeneous, being made up of only one phase. Other mixtures, containing more than one phase, are called heterogeneous.
Solutions - Solutions are a special type of homogeneous material, because unlike compounds, the parts of a solution are physically, not chemically, combined. When you mix a glass of salt water, the salt does not chemically react with the water. The two parts just mix so well that the resultant solution is said to be uniform. Ice tea, coffee, metal alloys, and the air we breathe are some examples of solutions.
Solutions are made up of two parts: The solute, which gets dissolved, and the solvent, which does the dissolving. In the case of salt water, salt is the solute and water is the solvent.
Heterogeneous mixtures - Heterogeneous mixtures are made up of more than one phase and they can be separated physically. The aforementioned chocolate chip cookie, a tossed salad, sand, and a bowl of raisin bran cereal are all examples of obvious heterogeneous mixtures.
Anything that has mass and volume is matter. All of the solids, liquids and gases that you may encounter in your daily life would be classified as some type of matter. You are familiar with the taxonomy of living things from Biology. Now you will learn how scientists classify matter that makes up everything.
Substance - A material with a constant composition. This means that the substance is the same no matter where it is found. NaCl, H2O, Ne, CO2, and O2 are all substances, because their composition will be the same no matter where you find them. All elements and all compounds are defined as substances.
Elements - Elements are substances that are made up of only one type of atom. At this time, there are 113 known elements, most of which are metals. The symbols shown on the periodic table represent the known elements.
Compounds - Compounds are substances that are made up of more than one type of atom. Water, for example, is made up of hydrogen and oxygen atoms. Carbon dioxide is made up of carbon and oxygen atoms. Table salt is made up of sodium and chlorine. Compounds differ from mixtures in that they are chemically combined. Unlike elements, compounds can be decomposed, or broken down by simple chemical reactions.
Phase - A phase is any region of a material that has its own set of properties. In a chocolate chip cookie the dough and the chips have different properties. Therefore they represent separate phases. Pure gold, which is an element, would only contain one phase. Italian dressing would clearly represent several phases, while a solution of salt water may only contain one phase.
Homogeneous Materials - Any material that contains only one phase would be considered homogeneous. Elements like hydrogen, compounds like sugar, and solutions like salt water, are all considered homogeneous because they are uniform. Each region of a sample is identical to all other regions of the same sample.
Mixtures - Mixtures are made up of two or more substances that are physically combined. The specific composition will vary from sample to sample. Some mixtures are so well blended that they are considered homogeneous, being made up of only one phase. Other mixtures, containing more than one phase, are called heterogeneous.
Solutions - Solutions are a special type of homogeneous material, because unlike compounds, the parts of a solution are physically, not chemically, combined. When you mix a glass of salt water, the salt does not chemically react with the water. The two parts just mix so well that the resultant solution is said to be uniform. Ice tea, coffee, metal alloys, and the air we breathe are some examples of solutions.
Solutions are made up of two parts: The solute, which gets dissolved, and the solvent, which does the dissolving. In the case of salt water, salt is the solute and water is the solvent.
Heterogeneous mixtures - Heterogeneous mixtures are made up of more than one phase and they can be separated physically. The aforementioned chocolate chip cookie, a tossed salad, sand, and a bowl of raisin bran cereal are all examples of obvious heterogeneous mixtures.
List of Topics:
Chapter 1: Classifying Matter
1.1 What is Matter
1.2 Particle Theory
1.4 Pure Substances & Mixtures
1.6 Mechanical Mixtures & Solutions
Chapter 1: Classifying Matter
1.1 What is Matter
1.2 Particle Theory
1.4 Pure Substances & Mixtures
1.6 Mechanical Mixtures & Solutions
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Chapter 2: Solutions
2.1 Solutes and Solvents
2.2 Dissolving and the Particle Theory
2.3 Concentration and Solubility
2.1 Solutes and Solvents
2.2 Dissolving and the Particle Theory
2.3 Concentration and Solubility
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Chapter 3: Separating Mixtures
3.2 Separating Mechanical Mixtures
3.4 Protecting the Environment by Separating Mixtures
3.5 Separating Solutions
3.7 Mixtures in Industry
3.2 Separating Mechanical Mixtures
3.4 Protecting the Environment by Separating Mixtures
3.5 Separating Solutions
3.7 Mixtures in Industry
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