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21 Cards in this Set
- Front
- Back
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What is a molecule? |
A group of two or more atoms joined together by covalent bonds |
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What is a mole? |
One mole (mol) is the amount of substance that contains as many particles as there are atoms in exactly 12g of carbon-12 |
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Define what the Empirical Formula is |
The empirical formula of a compound gives the simplest ratio of the number of atoms of each element present in a molecule |
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How do you calculate the Empirical Formula? |
1) Divide the mass/percentage composition of each element by its relative atomic mass (Ar) 2) Divide the answers by the smallest value. 3) Result should be answers in an obvious whole number ratio. |
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Define what the molecular formula is |
The molecular formula of a compound shows the actual numbers of the atoms of each element in the compound |
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How do you calculate the molecular formula? |
You compare the relative molecular mass of the substance with the formula mass of the Empirical Formula and deduce the the number. |
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How do you calculate the amount of a substance in moles? |
Amount in moles= mass of substance in grand/relative atomic(or molecular) mass |
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What is the ideal gas equation? |
pV=nRT and can be used for gases (or volatile liquids above their boiling temperatures) to find the amount of a substance in moles |
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What is p? |
Pressure in pascals (Pa) |
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What is V? |
Volume in cubic metres (m3) |
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What is T? |
Temperature in Kelvin (K) |
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What is n? |
Amount of substance in moles (mol) |
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What is R? |
The gas constant that has a value of 8.31 J mol-1 K-1 |
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What is the conversion from kPa to Pa? |
Multiply by 1000 |
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What is the conversion from cm3 to m3? |
Divide by 1000000 |
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What is the conversion from dm3 to m3? |
Divide by 1000 |
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What is the conversion from °C to K? |
Add 273 |
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How do you calculate the molar mass? |
Mass of substance in g/amount in mol= molar mass in g mol -1 |
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What is the equation for calculating moles? |
Amount of substance in moles= mass in grand/molar mass |
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What is the molar volume equation? |
24dm3 mol-1 (24000cm3 mol-1) = volume in dm3 (cm3)/amount in mol |
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How do you calculate the mass concentration? |
Mass concentration in g dm-3 = mass of solute in g/volume of solution in dm3 |
