A level Chemistry Study guides, Class notes & Summaries

What is heterolytic fission? Where one ion gets both electrons from the covalent bond What are produced by heterolytic fission? Ions What is a free radical? An atom or group with an unpaired electron, which is highly reactive as it wishes to pair up this electron What are 3 examples of situations where a free radical can be formed? During thermal cracking, during the reaction of halogens and methane, by homolytic fission What is homolytic fission? A reaction where each atom gets one el...

What are nucleons? Nucleons are protons and neutrons in the nucleus. What is the position of protons? Nucleus What is the relative mass of a proton 1 What is the relative charge of a proton? +1 What is the position of neutrons? Nucleus What is the relative mass of a neutron? 1

How to test for C=C decolourises bromine water Atomic Number number of protons in the nucleus of an atom of that element. Mass Number the sum of protons and neutrons in a nuclues of an atom Isotopes atoms of the same elementwith the same numberof protons but different nuber of neutrons Relative Atomic Mass the average mass of an atom of an element compared to a twelfth of the mass of an atom of carbon-12. Relative Isotopic Mass The mass of an atom of an isotope compared to one-twelfth ...

Periodic table Table that provides chemists with a structural organisation of the known chemical elements that can be used to deduce physical and chemical properties Atomic radius across Period 3 Decreases First ionisation energy across Period 3 Increases Exceptions: Drops at Al and S Melting points across Period 3 Increases from Na to Si Decreases from Si to Ar Small rise at S Explain why the melting point of aluminium is higher than the melting point of sodium Bigger charge (3+ comp...

Natures of amino acidspolar, non-polar, electrically-charged Properties of amino acidswhite crystalline solids, high melting point, soluble in H2O Effect of pH on enzyme activityincreases then decreases above the optimum pH Why does the enzyme activity decrease above optimum pH?the active site is changed due to the ionic bonds Describe the effect of substrate concentration on enzyme activityincreases then constant

Proton Mass 1 Proton Charge +1 Neutron Mass 1 Neutron Charge 0 Electron Mass 1/1840 Electron Charge -1

TOF steps 1) ionisation 2) acceleration 3) ion drift 4) detection 5) analysis Electron impact Sample vaporised and electron gun fires high energy electrons at it which knock off 1 electron from each particle, making them 1+ ions NB- can knock off more than one e or break molecular ion electrospray ionization Sample dissolved in volatile solvent then injected through needle to give fine mist which is attached to positive end of high voltage power supply, particles gain proton NB- ...

Topic 1 Atomic Structure Topic 2 Amount of Substance State what is meant by the term molecular formula. the actual no. atoms of each element in a compound Topic 3 Bonding Explain why CF4 has a bond angle of 109.5°. -there are 4 bonding pairs and no lone pairs -repel equally and therefore spread apart as far as possible Topic 4 Energetics State and explain change in the volume of water in calorimetry that would cause a reduction in heat loss. -higher volume -smaller increase in tem...

Bronsted-Lowry acid Proton donor Bronsted-Lowry base Proton acceptor pH Measure of acidity by measuring concentration of H⁺ ions. Low pH means Acidity High pH means Alkalinity

Silver nitrate+ nitric acid + iodide ions Yellow precipitate Silver nitrate+ nitric acid + bromide ions Cream precipitate Silver nitrate+ nitric acid + iodide ions Yellow precipitate Substances that decolorise bromine water Alkenes Electrophiles Electron pair acceptors, attracted to electrons e.g H+ NaF and NaCl Produces misty fumes with conc sulphuric acid