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What is chemistry?
The study of the composition, structure and propeties of matter and the changes that it undergoes.
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Pure/Basic Research vs. Applied Research
Pure-
Applied-
- Pure- development of knowledge (discovery of new elements)
- Applied- technology directly used for specific goals. (teflon: nonstick layer on pans)
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What is mass?
The amount of matter that an object contains. (unaffected by gravity)
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What is weight?
- The mass of substance times the fore of gravity whereas mass is unaffected by gravity.
- -mass x gravity (gravity on earth=9.8 m/s2)
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What is matter?
Anything that has mass and takes up space. (volume)
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What are atoms?
The smallest unit of an element that maintains the properties of that element.
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What is an element?
- A pure substance mad of only one kind of atom.
- -Examples: Na, C, Br, Cl, Mg
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What is a compound?
- A substance that is made from the atoms of 2 or more elements that are chmically bonded together.
- -substances that can be seperated into simpler substances by chemical reactions.
- -Eamples: NaCl, MgO, H2O
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Both elements and compounds are considered what?
pure substances
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What are Extensive Properties?
- Deends on the size of the sample of substance.
- Examples: mass, volume, weight, heat absorbed
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What are Intensive Properties?
- Does not depend on the size of the sample of substance and is true for any sample of that substance.
- Examples: density, color, boiling point, freezing point, etc.
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What are Physical Properties?
- Property that does not change the compostion of a substance.
- Examples: dissolving, condensing, grinding.
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What is a physical change?
- A change that does not involve a change in the identity of a substance.
- Examples: melting ice, painting wood, breaking glass, dissolving salt in water, etc.
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What are the 3 common states of matter?
Solid, liquid and gas.
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Describe a solid.
Matter with definite shape and matter. Molecules are tight and cannot move much so they vibrate.
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Describe a Liquid.
Matter that flows, has a fixed volume and takes the shape of its container. More room to move around than a solid. Molecules do not move in straight line.
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Describe a Gas.
Matter that takes both shape and volume of its container. Molecules move very fast and in straight lines; they have much more room to move that solids or liquids.
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Solid to Liquid-
Solid to Gas-
Liquid to Gas-
Liquid to Solid-
Gas to Solid-
Gas to Liquid-
- melting
- sublimation
- vaporization
- freezing
- deposition
- condensation
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What are chemical properties?
- A property that changes chemical composition of the substance resulting in a new one.
- Examples: rusting, corroding, digesting, etc.
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What is a Chemical Change?
A change in which one or more of the substances are converted into different substances.
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