Chemistry - Atoms, Moles and Equations

OCR AS Chemistry unit 1.1.1 and 1.1.2 - Atoms & Moles and Equations.

Written from spec and text book. Should include everything you need to know on these topics apart from calculations, however you must do practice papers and past questions as well. 

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Describe protons, neutrons and electrons in terms of relative mass and charge.
Proton = mass - 1.0, charge -1+. Neutron = mass - 1.0, charge - 0. Electron = mass - 1/2000, charge - 1-.
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What is atomic number?
The number of protons in the nucleus.
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What is mass number?
The number of protons and neutrons in the nucleus.
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Define the term Isotope.
Atoms of an element with different numbers of neutrons and different masses.
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What is used as the standard measurement for relative masses?
carbon-12
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Define the term relative isotopic mass.
The mass of an atom of an isotope compared with one-twelth of the mass of an atom of carbon-12.
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Define the term relative atomic mass.
The weighted mean mass of an atom of an element compared with one-twelth of the mass of an atom of carbon-12.
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Define relative molecular mass.
The weighted mean mass of a molecule compared with one-twelfth of the mass of an atom of carbon-12.
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Define the term relative formula mass.
The weighted mean mass of a formula unit compared with one-twelfth of the mass of an atom of carbon-12.
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When would you use relative molecular mass to measure the mass of a compound/element rather than relative formula mass?
With simple molecules such as: N2, O2 and CO2. Relative formula mass is for giant structures that do not exist as simple molecules. e.g. NaCl
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Explain the term - Amount of Substance.
the quantity whose unit in the mole.
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Explain the term - A Mole.
Mole = The unit for amount of substance. A Mole = It is the amount of any substance containing as many particles as there are carbon atoms in exactly 12 g of the carbon-12 isotope.
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Define the term Molar mass and give the units.
The mass per mole of a subtance. Units, g mol-1.
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Explain the term empirical formula.
The simplest whole number ratio of atoms of each element present in a compound.
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Explain the term molecular formula.
The actual number of atoms of each element in a molecule.
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What is the equation for calculations, using amount of substance in a mole, involving mass?
n(moles) = mass(m) / molar mass(M)
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What is the equation for calculations, using amount of substance in a mole, involving gas volume?
n(moles) = Volume(dm3) / 24 OR n(moles) = Volume(cm3) / 24000
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What is the equation for calculations, using amount of substance in a mole, involving solutions.
n(moles) = Concentration x Volume (dm3). Divide volume by 1000 if you are using cm3.
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Other cards in this set

Card 2

Front

What is atomic number?

Back

The number of protons in the nucleus.

Card 3

Front

What is mass number?

Back

Preview of the front of card 3

Card 4

Front

Define the term Isotope.

Back

Preview of the front of card 4

Card 5

Front

What is used as the standard measurement for relative masses?

Back

Preview of the front of card 5
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