* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Equilibria PPT
Ultraviolet–visible spectroscopy wikipedia , lookup
Statistical mechanics wikipedia , lookup
Thermodynamics wikipedia , lookup
Thermodynamic equilibrium wikipedia , lookup
Acid dissociation constant wikipedia , lookup
Electrochemistry wikipedia , lookup
Marcus theory wikipedia , lookup
Woodward–Hoffmann rules wikipedia , lookup
Detailed balance wikipedia , lookup
Stability constants of complexes wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Nucleophilic acyl substitution wikipedia , lookup
Acid–base reaction wikipedia , lookup
Enzyme catalysis wikipedia , lookup
Ene reaction wikipedia , lookup
Hydrogen-bond catalysis wikipedia , lookup
Industrial catalysts wikipedia , lookup
Reaction progress kinetic analysis wikipedia , lookup
Rate equation wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
George S. Hammond wikipedia , lookup
Determination of equilibrium constants wikipedia , lookup
Transition state theory wikipedia , lookup
Delivery Guide (Learner Resource) Equilibria H070 H470Topic TopicTitle Title © OCR 2016 • Most chemical reactions can only go one way. The reaction of methane and oxygen for example: CH4(g) + O2(g) CO2(g) + 2H2O(l) • It is almost impossible to return the carbon dioxide and water to the original methane and oxygen. © OCR 2016 • Some chemical reactions, however, will go backwards and forwards depending on the conditions. CoCl 2.6H2O(s) CoCl 2(s) + 6H2O(l) pink blue This is the symbol for used for reversible reactions. CoCl2·6H2O(s) © OCR 2016 CoCl2(s) + 6H2O(l) Equilibrium • Reversible reactions reach a balance point, where the amount of reactants and the amount of products formed remains constant. • Most common misconception is that they are equal. This is not the case. They remain constant. © OCR 2016 Position of the equilibrium • Equilibrium can “lie” to the left or right. • This is “in favour of products or the forward reaction” or “in favour of reactants or the reverse reaction” • Meaning that once equilibrium has been reached there could be more products or more reactants in the reaction vessel. LEFT RIGHT (REACTANTS) (PRODUCTS) © OCR 2016 Le Chatelier’s principle involving AMOUNT or CONCENTRATION • If you increase A or B you will make more C or D so it will FAVOUR the forward reaction and the equilibrium will LIE to the right. A B C D • If you increase C or D you will make more A or B so it will FAVOUR the reverse reaction and the equilibrium will LIE to the left. © OCR 2016 Le Chatelier’s principle involving TEMPERATURE • If you increase the temperature of an EXOTHERMIC REACTION the reaction will try to cool it down so will FAVOUR the reverse reaction and equilibrium will LIE to the left A B C D HEAT • If you cool down an EXOTHERMIC REACTION it will try to increase the heat so will FAVOUR the forward reaction and equilibrium will LIE to the right. • NB: If it is exothermic forward, it will be endothermic in reverse. © OCR 2016 Le Chatelier’s principle involving PRESSURE • If you increase the pressure it will favour the reaction with the smallest number of moles. In this case it would FAVOUR the reverse reaction and equilibrium will LIE to the left. A B C D E • If you lower the pressure it will favour the reaction with the most number of moles. In this case it would FAVOUR the forward reaction and equilibrium would LIE to the right. © OCR 2016 Strong and weak acids • A strong acid is one which is FULLY IONISED in water. It will have a high hydrogen ion concentration in this case ALL of the H+ is made so strong acid pH1 • A weak acid is one which is NOT fully ionised and is in equilibrium. It has a low hydrogen ion concentration In this case there are SOME H+ but not ALL so this makes the acid weaker (ie pH3) . EQUILIBRIUM DOES NOT LIE TO THE RIGHT. © OCR 2016 • http://www.youtube.com/watch?v=iWpfHkWr5DY • http://www.youtube.com/watch?v=zVZXq64HSV4 • http://www.youtube.com/watch?v=0XQVXFL4uoo • http://www.youtube.com/watch?v=YMqyG9QG6oc OCR Resources: the small print OCR’s resources are provided to support the teaching of OCR specifications, but in no way constitute an endorsed teaching method that is required by the Board, and the decision to use them lies with the individual teacher. Whilst every effort is made to ensure the accuracy of the content, OCR cannot be held responsible for any errors or omissions within these resources. © OCR 2015 - This resource may be freely copied and distributed, as long as the OCR logo and this message remain intact and OCR is acknowledged as the originator of this work. OCR acknowledges the use of the following content: Please get in touch if you want to discuss the accessibility of resources we offer to support delivery of our qualifications: [email protected] © OCR 2016