OCR A A Level CHEMISTRY PAPER 1 questions and solutions

OCR A A Level CHEMISTRY PAPER 1
questions and solutions
Test for carbonates - Correct Answer ✔✔ - - add dilute HCL
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




- it makes carbon dioxide
,b ,b ,b ,b ,b




test for carbon dioxide by bubbling it through lime water
,b ,b ,b ,b ,b ,b ,b ,b ,b




Test for ammonium ions - Correct Answer ✔✔ - -add sodium hydroxide
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




-warm the mixture ,b ,b ,b




-hover damp red litmus paper over it , if it turns blue the ions are present
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




Test for sulphate ionz (SO4 2-) - Correct Answer ✔✔ - - add dilute HCL
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




- then add BaCl2
,b ,b ,b




- BaSO4 is made which is insoluble in water so a white precipitate will be formed
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




Test for Halides (Cl-, Br-, I-) - Correct Answer ✔✔ - - add nitric acid
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




- add silver nitrate
,b ,b ,b ,b




- precipitates will be formed
,b ,b ,b ,b ,b




- Cl (white) , Br (cream) , I (yellow)
,b ,b ,b ,b ,b ,b ,b ,b




Why add dilute acids when testing for ions ? - Correct Answer ✔✔ - it will get rid of any lurking
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




anions that may create false positives
,b ,b ,b ,b ,b ,b




Endothermic energy profile diagram - Correct Answer ✔✔ - products are higher than ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




reactants
,b




Exothermic energy profile diagram - Correct Answer ✔✔ - reactants are higher than ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




products
,b




What are standard conditions? - Correct Answer ✔✔ - 298K and 100kPa
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




Enthalpy change of reaction - Correct Answer ✔✔ - the enthalpy change when the reaction
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




occurs in molar quantities shown in the chemical equation under standard conditions
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




Enthalpy change of formation - Correct Answer ✔✔ - the enthalpy change when 1 mole of
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




compound is formed from it's elements in their standard states under standard conditions
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




Enthalpy change of combustion - Correct Answer ✔✔ - the enthalpy change when 1 mole of a
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




substance is burned completely in oxygen under standard conditions
,b ,b ,b ,b ,b ,b ,b ,b ,b




Enthalpy change of neutralisation - Correct Answer ✔✔ - the enthalpy change when an acid
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b




and alkali react under standard conditions to form 1 mole of water
,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b ,b