Chapter 4 Glossary Terms

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Chapter 4 Glossary Terms
2014-11-18 19:11:39
msday science

Chapter 4 Glossary Terms
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  1. What is matter?
    It is anything that has a mass and occupies space. e.g. your computer, your textbook, and even air! Knowing about the properties of matter can help you know how hazardous materials are and what is safest to handle them.
  2. What is a pure substance?
    It is a matter that contains only one kind of particle. A pure substance is something that matter can be classified by based on the particle theory of matter. e.g. water, oxygen, gold, neon...
  3. What is a mixture?
    It is a matter that contains more than one kind of particle. It is something that matter can be classified by based on the particle theory of matter. e.g. salt water, a combination of salt (sodium & chlorine) and water, or the air we breath,...
  4. What is an element?
    It is a pure substance that cannot be broken down into simpler parts by chemical methods. Heating, crushing, etc will not change the element into a simpler form. e.g. helium, which is used for balloons and etc, but cannot be changed into a simpler form.
  5. What is a compound?
    It is a pure substance that is made of two or more elements that are chemically combined. For example, water, which is made up of two elements: Hydrogen and Oxygen. A compound can be broken down to the original elements using chemical methods. For example, a process called electrolysis is used to separate hydrogen and oxygen.
  6. What is a physical property?
    It is a characteristic of a substance that can be observed and measured without changing the identity of the substance. This is important so we can determine the practical uses of the substances.
  7. What is viscosity?
    The measure of a substance's resistance to flow (or how easily a fluid flows). A substance flows more slowly when it is more viscous.
  8. What is the melting/boiling point of a substance?
    The melting point is the temperature at which a solid turns into a liquid, while the boiling point is the temperature at which a liquid turns into a gas. For example, the boiling point of water is 100 C, while water doesn't have a melting point.
  9. What is the solubility of a substance?
    It is the measure of a substance to dissolve in another substance. It is recorded as the highest quantity  of a substance that is dissolved in a solvent at a specific temperature and pressure. Solubility is also expressed as a concentration. If large amounts of a substance dissolve in a substance, it is considered highly soluble.
  10. What is density?
    The ratio of the mass of a substance to the volume it occupies. For a certain mass of a substance, there is a certain volume required. Density is a property of liquids, gases, and solids. To calculate density, the equation D= m/V is used.
  11. What is a chemical property?
    The ability of a substance to change or react and form new substances.  Different compounds react with each other to produce a new substance.
  12. What is combustibility?
    The ability of a substance to burn in air. e.g. propane, which reacts with oxygen in the air and releases a large amount of heat, but the combustibility of propane is hazardous.
  13. What is stability?
    The ability of a substance to remain unchanged, or to how easily the substance decomposes or breaks down. The more stable a substance is, the longer it will take to decompose/break down.
  14. What is toxicity?
    The ability of a substance to cause harmful effects in plants and animals. Most chemicals are poisonous of there is a high enough concentration.