5 Titration curves PAG11

 

/
~
~
~
/

 

Show Learning Materials


Oxford Textbook Pages : 340 - 343

CGP Revision Guide Pages : 142 - 143

/
/
/
/

Show Specification Ref : 5.1.3n, 5.1.3o, PAG11

/
/
/
/
Show past exam questions

Question 1 / 5

AQA Jan 2010 Paper 4 Q2 areas outside the box will not be scanned for marking in this question give all values of ph to decimal places a i write an expression for the term ph mark a ii calculate the concentration in mol dm of an aqueous solution of sulfuric acid that has a ph of marks b a student carried out a titration by adding an aqueous solution of sodium hydroxide from a burette to an aqueous solution of ethanoic acid the end point was reached when cm of the sodium hydroxide solution had been added to cm of mol dm ethanoic acid b i write an equation for the reaction between sodium hydroxide and ethanoic acid mark b ii calculate the concentration in mol dm of the sodium hydroxide solution used marks wmp jan chem b iii a list of indicators is shown below areas outside the box will not be scanned for marking indicator thymol blue bromophenol blue litmus cresol purple ph range select from the list the most suitable indicator for the end point of this titration mark b iv suggest why the concentration of sodium hydroxide in a solution slowly decreases when left open to air mark c at k the value of the acid dissociation constant ka for ethanoic acid in aqueous solution is mol dm c i write an expression for the acid dissociation constant ka for ethanoic acid mark c ii calculate the ph of mol dm ethanoic acid at this temperature marks extra space question continues on the next page turn over wmp jan chem areas outside the box will not be scanned for marking c iii calculate the ph of the buffer solution formed when cm of mol dm potassium hydroxide are added to cm of mol dm ethanoic acid marks extra space wmp jan chem there are no questions printed on this page do not write on this page answer in the spaces provided turn over wmp jan chem
Show answer

Question 2 / 5

AQA Jun 2011 Paper 4 Q1 section a answer all questions in the spaces provided do not write outside the box titration curves labelled a b c and d for combinations of different aqueous solutions of acids and bases are shown below all solutions have a concentration of mol dm ph ph volume cm volume cm ph ph volume cm volume cm a in this part of the question write the appropriate letter in each box from the curves a b c and d choose the curve produced by the addition of ammonia to cm of hydrochloric acid sodium hydroxide to cm of ethanoic acid nitric acid to cm of potassium hydroxide marks wmp jun chem do not write outside the box b a table of acid base indicators is shown below the ph ranges over which the indicators change colour and their colours in acid and alkali are also shown indicator trapaeolin bromocresol green cresol purple alizarin yellow ph range colour in acid colour in alkali red yellow yellow yellow yellow blue purple orange b i select from the table an indicator that could be used in the titration that produces curve b but not in the titration that produces curve a mark b ii give the colour change at the end point of the titration that produces curve d when cresol purple is used as the indicator mark turn over for the next question turn over wmp jun chem
Show answer

Question 3 / 5

AQA Jun 2015 Paper 4 Q3 do not write outside the box titration curves labelled e f g and h for combinations of different aqueous solutions of acids and bases are shown in figure all solutions have concentrations of mol dm figure ph ph volume cm volume cm ph ph volume cm volume cm a in this part of the question write the appropriate letter in each box from the curves e f g and h choose the curve produced by the addition of a i sodium hydroxide to cm of ethanoic acid a ii ammonia to cm hydrobromic acid a iii hydrochloric acid to cm of potassium hydroxide mark mark mark wmp jun chem do not write outside the box b table shows information about some acid base indicators table indicator ph range lower ph colour higher ph colour pentamethoxy red naphthyl red nitrophenol cresol purple violet red colourless yellow colourless yellow yellow purple b i which indicator in table could be used for the titration that produces curve e but not for the titration that produces curve f mark tick one box pentamethoxy red naphthyl red nitrophenol cresol purple b ii give the colour change at the end point of the titration that produces curve h when naphthyl red is used as the indicator mark b iii a beaker contains cm of a buffer solution at ph two drops of each of the four indicators in table are added to this solution state the colour of the mixture of indicators in this buffer solution you should assume that the indicators do not react with each other mark turn over wmp jun chem
Show answer

Question 4 / 5

AQA Jun 2013 Paper 5 Q6 do not write outside the box this diagram represents the energy change that occurs when a d electron in a transition metal ion is excited by visible light e excited state ground state a give the equation that relates the energy change e to the planck constant h and the frequency of the visible light v use this equation and the information in the diagram to calculate a value for the frequency of the visible light and state the units the planck constant h j s equation calculation marks b explain why this electron transition causes a solution containing the transition metal ion to be coloured marks wmp jun chem do not write outside the box c the energy change shown in the diagram represents the energy of red light and leads to a solution that appears blue blue light has a higher frequency than red light suggest whether the energy change e will be bigger smaller or the same for a transition metal ion that forms a red solution explain your answer energy change explanation marks d state three different features of transition metal complexes that cause a change in the value of e the energy change between the ground state and the excited state of the d electrons feature feature feature marks turn over for the next question turn over wmp jun chem
Show answer

Question 5 / 5

AQA Jun 2015 Paper 5 Q9 do not write outside the box the redox reaction in aqueous solution between acidified potassium manganate vii and sodium ethanedioate is autocatalysed a write an equation for this redox reaction identify the species that acts as the catalyst explain how the properties of the species enable it to act as a catalyst in this reaction marks wmp jun chem do not write outside the box b sketch a graph to show how the concentration of mno reaction explain the shape of the graph ions varies with time in this marks end of questions wmp jun chem
Show answer
/
/
/
/
/
/