Salters chemistry (OCR B)- Unit 1

Precise key revison notes on chemistry for life (F331) of salters chemistry, OCR B specification.

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AS Chemistry Revision-Chemistry for Life
1. Avagadro constant, 6.02 x 10²³
number of particles in 1 mole of a substance
2. Empirical formula-simplest ratio of atoms of each element in a compound
3. M oles = Mass
4. Model of an atom
Particle Mass on relative atomic scale Charg
Proton 1 1+
Neutron 1 0
Electron Very small (0.00055) 1-
5. Radioactive isotopes
Radiation What is it? Relative How does the Stopped by? Deflection in
charge nucleus change? electric field?
Alpha Helium nuclei +2 2 fewer protons Paper or skin Low
He 2 fewer neutrons
Beta Electrons -1 1 more proton Aluminium High
°e 1 fewer neutron foil
Gamma Electromagneti none No change Lead sheet None
c radiation
i. The time taken for half a radioactive isotope/substance to decay.
ii. Not affected my temperature
iii. Can be used to date archaeological artefacts made from living things
i. Radioactive isotopes whose decay is monitored
ii. Can be used to aid diagnosis, followed by a Geiger counter
iii. An isotope should have a half-life which is neither too short or it will decay
before tracing is complete. nor too long or it will persist for too long in the body,
potentially causing harm to the patient.
7. Absorption spectra
Coloured background with black lines
Lines go up
Lines get closer at higher frequency
Produced when:
i. Electrons absorb a photon (package of energy) and become excited.

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Excited electrons move to a higher energy state- they are promoted
iii. The electromagnetic radiation absorbed by each atom has a definite frequency
related to the difference in energy levels by E = hv
8. Emission spectra
Black background with coloured lines
Lines go down
Lines get closer at higher frequency
Produced when:
i. Electrons first absorb a photon and become excited
ii. Excited electrons move up to higher energy level
iii. Electrons drop back to lower energy level and emit electromagnetic radiation
iv.…read more

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­ pyramidal- 109°
iii. 2 bonding pairs and 2 lone pairs ­ bent- 109°
3 groups of electrons ­ planar triangular - 120°
2 groups of electrons ­ linear - 180°
11.…read more

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Poison is strongly absorbed onto the catalyst surface
ii. The poison blocks the catalyst surface, preventing reactants from bonding.
13. Mass spectrometer
Sample inlet-
Ionisation area- electrons produced by a heated filament bombard any atoms or
molecules in the sample and knock electrons out. Cations (positive ions) are formed:
X + e¯ X + 2e¯
Produces fragments.
Acceleration are- an electric field accelerates any ions so that they all have the same
kinetic enbergy.…read more

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Calculate energy transferred using:
Energy transferred (J) = m x c x T
Mass, specific heat capacity and change in temperature
ii. Calculate the moles of the fuel used using:
M oles = Mass ofMr
fuel used
iii. Enthalpy of combustion (kJmol¯¹)
=energy transferred (kJ )
moles of fuel used
15.…read more

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Structural isomerism
Chain isomerism- i.e. unbranched chains to branched chains
Positional isomerism- i.e. pentan-1-ol and pentan-2-ol
Functional group isomerism- same molecular formula but the functional groups are
different. i.e. ethanol and methoxymethane
18. Increasing octane number
i. Produces shorter, branched alkane + alkene
ii. Use of zeolite catalyst
i. Converts alkanes into cycloalkanes + hydrogen
ii. Converts cycloalkanes into arenes + hydrogen
iii. Use of platinum catalyst
i. Produces shorter, more branched alkanes
ii.…read more

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Outermost electrons is further away from the nucleus down a group
o This makes electrons less firmly held by the nucleus (weaker attraction)
o Therefore electrons require less energy to remove
Isotopes-atoms of the same element that have the same number of proton but different
numbers of neutrons
Symbol for electron in ionisation enthalpies = e¯
Symbol for electron in alpha-particles = °e
Diesel produces more particulates than petrol due to:
o Diesel has a lower operating temperature than petrol
o Longer molecules in diesel…read more


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