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16 Cards in this Set
- Front
- Back
what is matter ? |
Anything that has mass and occupies space |
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Pure matter / substance |
A substance is said to be pure if it contain only one component. |
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What is an element ? |
A pure substance that is made of the same type of atoms |
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What is a compound ? |
A pure substances which is formed when the atoms of two or more elements combine chemically. -> Oxygen |
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Heating Curves |
A Heating curve is obtained by heating a pure substances and measuring the change in temperature over time |
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What is a atom ? |
The smallest particle in which an element can exist with losing properties of that element |
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Sub-atomic particles They are : |
-The atoms has a central nucleus that contain protons and neutrons |
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All compounds are made up of molecules |
pure substances have a fixed or constant boiling and melting point |
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Impure substances |
A substance is said to be impure if it contains more than one components. They are also called mixtures Example: soda, ice-cream, soup |
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You can know if a substances is pure or impure by measuring it melting or boiling point. |
Impure substances boil over a narrow range of temperatures. |
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Atomic number = number of protons = number of electrons Mass number = number of protons + number of neutrons Number of neutrons = mass number - number of protons |
Arrangement of electrons in atoms 2nd shell - 8 electrons 3rd shell - 8 electrons |
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What is electronic configuration ? |
The arrangement of electrons on the shell of the atoms |
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How to determine if a liquid is pure or impure |
Heat both liquids and measure the boiling point with a thermometer. If the liquid is pure it would boil at a fixed temperature and if the liquid is impure it would boil over a narrow range of temperatures. |
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Change of state gas - liquid = condensation liquid - gas = evaporation liquid - solid = freezing gas - solid = sublimation |
Examples of solids that undergo sublimation - dry ice - camphor balls - Iodine ( purple) |
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Difference between boiling and evaporation |
- evaporation occurs on the surface of liquids while boiling occurs through out the liquid - evaporation occurs at any temperature while boiling occurs at a fixed temperature |
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-Elements are arranged in order of their increasing atomic number in the periodic table - for the first 20 elements, those whose name end with ' ium ' except helium are metals. They are: lithium , beryllium, sodium , calcium, magnesium, potassium and aluminium. |
Compounds in living systems some compounds are common in both plants and animals. they include: carbohydrates- they contain the elements carbon, hydrogen, oxygen examples : glucose , sucrose and starch primary functions : Provide energy |