No atoms are lost or made during chemical reaction, so the mass of products is equal to the mass of reactants.
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What is the relative formula mass or Mr
The sum of the relative atomic masses (Ar) of the atoms in the numbers shown in a compounds formula.
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What is the equation used to work out percentage mass?
(mass of element / mass of compound) x 100
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Why might a chemical reaction show a change in mass?
One products or reactants could be a gas and mass is not taken into acount.
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What is the units for mole?
Mol
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One mole of a substance is equal to what in grams...
Equal to the relative atomic mass.
Eg 1 mole of carbon has 12g.
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What is Avogardo's constant?
6.02x10 23 per mole.
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How many atoms would be in 1 mole of carbon?
6.02 x 10 23 atoms.
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How many atoms would there be in 1 mole of carbon dioxide?
6.02 x 10 23 atoms.
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How many atoms would there be in 16g of Oxygen?
6.02 x 10 23 atoms.
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Why is one reactant in excess?
To ensure the other reactant (limiting) is completely use up.
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How do you get from cm3 to dm3?
divide by 1000
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What is the equation for percentage yield?
(mass of product actually made / theoretical mass of product ) x 100
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Why might the theoretical yield not be obtained?
- reaction may be reversible and not go to completion
- some product may be lost when separated from reaction mixture
- some reactants may react differently than expected.
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What is the equation for atom economy?
(Mr of desired product / sum of Mr of all reactants) x 100
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Why is it important to have reactions with high atom economy?
For sustainable development and for economic reasons.
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What is the unit for concentration of a solution?
mol/dm3
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Under room temperature and pressure, what is the volume one mole of gas can occupy?
24dm3
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What is the equation for moles?
moles = mass / Mr
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What is the equal for moles using volume and concentration
moles = concentration x volume
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What is the equation for calculating volume of gas using 24dm3?
volume = moles x 24dm3
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Other cards in this set
Card 2
Front
What is the relative formula mass or Mr
Back
The sum of the relative atomic masses (Ar) of the atoms in the numbers shown in a compounds formula.
Card 3
Front
What is the equation used to work out percentage mass?
Back
Card 4
Front
Why might a chemical reaction show a change in mass?
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