Chemistry Unit 1

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  • Created by: Sopha8
  • Created on: 29-04-14 20:38
What is an isotope?
Atoms with same number of protons but different neutron number
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Definition of relative atomic mass
The average mass of an atom of an element on a scale where carbon-12 is exactly 12
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Explain the 5 stages of mass spectrometry
1-vaporiation:turn into gas using electric heater, 2-ionisation:bombarded high engergy electrons, positive ions,3-acceleration:by electric field, 4-deflection:alter strength of fiel,5-detection:increase so ions with highest mass/charge reach detector
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How do you calculate relative atomic mass from mass spectrum?
multiply abundance of each peak, add totals, divide by 100
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What is an orbital? what are the 3 orbitals?
Space quite close to nucleus where electrons are found. s, p and d
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Define first ionisation energy
energy required to remove 1 electron from each atom in 1 mol of gaseous atoms to form 1mol of gaseos 1+ ions
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What are the factors affecting ionisation energy?
1-nuclear charge, 2-distance from nulcues: attraction falls rapidly with distance, 3-shielding:greater=lower ionisation energy
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How do you work out % yield and atom economy?
%yield=actual / theoretical x 100, %atom economy=mass of desired product / total mass of reactants x 100
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What are charge clouds? order elecron pairs from least to most repulsion
places that an electron is most likely to be found in. bonding+bonding, bonding+lone, lone+lone
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What is electronegativity? what can it cause? whats the trend along the groups?
the ability of an atom to attract the bonding electrons in a covalent bond, differences in electronagativity cause change in electron denisty-cause polarisation-leads to dipole, increases as higher nulcear charge
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Explain the 3 types of intermolecular bonding in order of strength
1) hydrogen-H with F/O/N, bonds polarised so hydrogen bond with lone pairs, 2)permanent dipole-+ and - charges cause weak electrostatic atttaction, 3)van der waals-charge clouds move-temporary dipole created and destroyed constantly
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What are the 4 trends of periodicity?
1)atomic radius decrease across period-protons increase 2)melting/boiling point relative to bonds 3)increase 1st ionisation energy along periods-higher nulcear charge 4)1st ionisation energy decrease down period 2
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What are the exceptions to the trends?
1)group 4-repel in opposite spin pairs, 3)drop between 2 and 3-outer electron in p orbital and 5 and 6- electron removed from orbital with 2 electrons
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Which formula shows the simpliest form of whole number atoms of each element in a compound?
Empiracle
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Give the general formulas of alkenes and alkanes
alkene-CnH2n, alkane-CnH2n+2
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What is a homologus series
series of organic compounds with same general formula, similar propertise but differ by 1 C atom
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What is a structural isomer? name the 3 types
compounds which have same molecular formual but atoms are connected in different ways, chain-different carbon skeleton, positional-groups attached in different places, functional group-different functional group
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What happens during fractional distillation?
crude oil seperated by heating as each fraction has different boiling point; gases, petrol, naptha, kerosene, gas oil, mineral oil and residue
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Which cracking produces alkene? which one produces branched alkanes and aromatic hydrocarbons?
1)thermal- 1000oc, 70atm 2)catalytic-zeolite , slight pressure, lower temps
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What are the formulas for alkanes in complete and incomplete combustion?
complete- alkane+oxygen--> carbon dioxide + water, incomplete- alkane+insufficient oxygen---> carbon +carbon dioxide + carbon monoxide+ water
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Other cards in this set

Card 2

Front

Definition of relative atomic mass

Back

The average mass of an atom of an element on a scale where carbon-12 is exactly 12

Card 3

Front

Explain the 5 stages of mass spectrometry

Back

Preview of the front of card 3

Card 4

Front

How do you calculate relative atomic mass from mass spectrum?

Back

Preview of the front of card 4

Card 5

Front

What is an orbital? what are the 3 orbitals?

Back

Preview of the front of card 5
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