C3 Exam Tips Feedback from the examiners The examiner says…

In the foundation paper if you get asked to write a word equation; remember to read the question carefully, most of the answer is normally in the question.

Even if you can’t do the whole equation still have a go at what you can do, you normally get one mark for the part before the arrow and one for the part after.

This test would work for carbon dioxide, but is not specific to carbon dioxide. Only the limewater test is acceptable, so this response did not score.

Read the question carefully, it asks you to ‘state how’ but this student has tried to ‘explain why’.

I’m lost for words…

When describing how to test for metal ions, don’t say that you will hold the wire loop OVER the flame. Nothing would happen.

Focus on what the question is asking rather than just putting down everything you know about a subject. Always show your working! Ensure you answer all parts of the question to maximise your marks. Be careful not to say two opposite statements in the same answer. Do not be afraid to use the information you have been given as part of your answer. Always read the question correctly to ensure that you are answering the question that is being asked rather than one you would like to be asked.

C2 Foundation Paper Summary Based on their performance on this paper, candidates are offered the following advice: read all the information in the question carefully and use this to help them answer the question. learn and use correct scientific terminology. learn the correct procedure for flame testing of ions and flame colours as in the specification. learn the specific conditions needed for fermentation and the equations associated with this process. learn the procedure for the preparation of an insoluble salt. be able to describe the processes occurring in electrolysis reactions in the specification and explain these in terms of redox processes occurring. practise writing extended writing tasks, addressing the whole question, often giving a scientific explanation to access higher levels.

C2 Higher Paper Summary On the basis of their performance on this paper. In order to improve their performance, candidates should: read all of the information in the question and use it to help them to answer the question; practise writing balanced equations, including ionic equations, for the reactions in the specification; practise carrying out calculations of the different styles in the specification; revise the tests to identify the ions in the specification; ensure that they can describe the different experiments that they have carried out in lessons, including titrations.

Mass Moles Relative atomic/ mole cular mass

Mass Moles Relative atomic/ mole cular mass If you need to calculate the number of moles

Mole Conc Volume

If in doubt change it to moles first If you are working with volumes of gas, this is not good advice as one mole of any gas always takes up 24dm 3 at room temperature and pressure.

If they want PURE crystals you can’t have any indicator in the solution you leave to evaporate. You need to use the indicator in your titration to find the volume of hydrochloric acid needed, and then repeat without indicator, adding the exact volume.

Flame tests are commonly used for CATIONS (metals). Precipitate reactions can also be used by reacting the ionic solution with SODIUM HYDROXIDE as most metal hydroxides are insoluble in water. Testing for Cations

Testing for the Halogens – This is performed by acidifying the sample with dilute Nitric Acid and then reacting with Silver Nitrate to form a precipitate. – This reaction works by the Halogen displacing the Nitrate in Silver Nitrate with the Halogen. Testing for Ammonium ions (NH 4 + ) – Warm the solution to release the Ammonium ions as a vapour – It will turn damp red litmus paper blue. Testing for anions

N H 2 ⇌ 2 NH 3 Making Ammonia

Making Ethanol 1. Fermentation 2. Hydration of Ethene (crude oil fraction) Making Ethene

Make Esters The ester

Convert concentration in g dm -3 into mol dm -3 and vice versa Mass Moles Relative atomic/ mole cular mass All your doing is changing g into mol or mol into g.

Calculate the concentration of solutions in gdm -3 Just think of it as g/dm 3 g dm 3 So do mass volume

To convert from cm 3 to dm 3 divide by a thousand.

GOOD LUCK FROM ALL THE SCIENCE TEACHERS AND TECHNICIANS