[AS Edexcel GCE Chemistry] HELP!Watch
1. demonstrate an understanding of the term: Amount of substance
2. a) carry out and interpret the results of simple test tube reactions, such as displacements, reactions of acids, precipitations, to relate the observations to the state symbols used in equations and to practise writing full and ionic equations.
3. I) plan and carry out an experiment where the enthalpy change cannot be measured directly, eg the enthalpy change for the decomposition of calcium carbonate using the enthalpy changes of reaction of calcium carbonate and calcium oxide with hydrochloric acid
4. I) deduce the isotopic composition of a sample of an element, eg polonium
5. I) deduce the relative atomic mass of an element
6. a) represent data, in a graphical form, for elements 1 to 36 and use this to explain the meaning of the term ‘periodic property’
7. a) use the models in 1.6.3a and 1.6.3b to interpret simple properties of metals, e.g. conductivity and melting temperatures.
1. a) apply the electron-pair repulsion theory to predict the shapes of molecules and ions analogous to those in 2.3b
2. a) demonstrate an understanding of the terms bond length and bond angle and predict approximate bond angles in simple molecules and ions
3. a) carry out experiments to study the solubility of simple molecules in different solvents
4. i) the solubility in non-aqueous solvents of compounds which have similar intermolecular forces to those in the solvent.
5. i) how oxidation number is a useful concept in terms of the classification of reactions as redox and as disproportionation
6. i) substitution reactions to form halogenoalkanes, including reaction with PCl5 and its use as a qualitative test for the presence of the –OH group
7. a) carry out the preparation of an halogenoalkanes from an alcohol and explain why a metal halide and concentrated sulfuric acid should not be used when making a bromoalkane or an iodoalkane
b) describe the typical behaviour of halogenoalkanes. This will be limited to treatment with:
i) aqueous alkali, eg KOH (aq)
ii) alcoholic potassium hydroxide
iii) water containing dissolved silver nitrate
iv) alcoholic ammonia
c) carry out the reactions described in 2.10.2d i, ii, iii
8. a) describe the mechanisms of the substitution reactions of halogenoalkanes and recall those in 1.7.2e and 1.7.3e
Amount of substance is just checking that you know what moles are and how to use them. Test tube reactions is about writing equations mainly so in the exam they might give you say a acid base neutralisation and ask you to write the ionic formula for it that kind of thing.
Indirect enthalpy change experiments involve using Hess's law to calculate by experiment enthalpy changes that can't directly be measured e.g.
In the thermal decomposition of NaHCO3 to Na2CO3 you can work this out indirectly. You know that a carbonate acid reaction gives a salt co2 and h2o and therefore in this case the salt formed is exactly the same. This means that you can set up a Hess cycle as on addition of HCl both form the same products (although you'll need to balance it). If you then work out experimentally the enthalpy of reaction when each one reacts with HCl with a bit of maths you can work out the enthalpy of reaction when it thermally decays.
I'm assuming that your deduce the isotopic composition is referring to mass spec. In monatomic mass specs each peak represents a different isotope of the element. To work out the relative atomic mass of the element you need to do a weighted average. Multiply the mass of each isotope by the relative abundance of it and add all these up. Then divide by the sum of all the relative abundances.
Periodic properties just means things that has trends across a period eg you might be asked to draw a graph of 1st ionisation energy as you move across a period and then using this explain certain trends.
The metallic question is just using knowledge of the metallic structure to explain the properties of metals. There is a strong attraction between the metal cations and the sea of delocalised electrons so as such a large amount of energy is needed to break this so they have high mp and bp. The delocalised electrons can also flow easily so metals are therefore very good conductors.
If you have any more questions or want me to answer the unit 2 ones let me know.
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