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15 Cards in this Set
- Front
- Back
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Law of conservation |
No atoms are made or lost during chemical reactions |
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Symbol equations have to be |
Balanced in the terms of atoms of each element on either side |
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What is the Mr or a compound |
Sum of the relative atomic masses of the atoms shown in the formula |
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In a balanced chemical equation the sum of the Mr of the reactants= |
Sum of Ar of the products |
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Why may some reactions appear to have a change in mass? |
A reactant or product could be a gas which it's mass has not been taken into account for |
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How are chemical amounts measured? |
Moles (mol) |
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What is one mol of a substance numerically equal to? |
Relative formula mass |
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What is avogadros constants? |
6.02 ×10 to the 23 |
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Formula for moles no. Particles |
Moles×avogadros constant=no . particles |
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Mass mole and mr |
Mass=mole×mr |
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How to work out reacting masses |
Balanced symbol equations Mr of each Mr taking into account amounts Convert to mass by adding units Scale to quantity needed by dividing |
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Limiting reactants |
Use an excess of one to use up all of the other Reactant that is all used up is called the limiting reactant |
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Why is it not always possible to obtain theoretical yield? |
Reaction is reversible Some product may be lost Some reactants may react in a unexpected way |
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How do u calculate percentage yeild |
Mass of products÷maximum theoretical yeild mass of product×100 |
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What's atom econemy |
Measurement of the amount of starting materials that ends up as useful products |
