OCR A level Chemistry

OCR A level Chemistry Exam With Questions And Answers Graded A+...

Test for carbonates - correct answer - add dilute HCL - it makes carbon dioxide test for carbon dioxide by bubbling it through lime water Test for ammonium ions - correct answer -add sodium hydroxide -warm the mixture -hover damp red litmus paper over it , if it turns blue the ions are present Test for sulphate ionz (SO4 2-) - correct answer - add dilute HCL - then add BaCl2 - BaSO4 is made which is insoluble in water so a white precipitate will be formed Test for Halides (Cl-,...

Relative isotopic mass - The mass of an isotope relative to 1/12 of the mass of a carbon-12 atom. Relative atomic mass Ar - The weighted mean mass of an atom of an element relative to 1/12 of the mass of a carbon-12 atom. Weighted: The percentage abundance of the isotopes of that element Mean: The relative isotopic mass of each isotope What is a mole? - The amount of substance containing as many particles as there are atoms in 12g of the carbon-12 isotope. This is 6.02 x 10^23 particles. ...

OCR A LEVEL CHEMISTRY A CHEMISTRY B SYNTHESIS OF AN ORGANIC LIQUID EXAM QUESTIONS AND CORRECT ANSWERKEY

acidA species that is a proton donor. activation energyThe minimum amount of kinetic energy that particles need to have in order to react when they collide addition polymerA very long molecular chain formed by repeated addition reactions of many unsaturated alkene molecules (monomers). addition polymerisationThe process in which unsaturated alkene molecules (monomers) add on to a growing polymer chain one at a time to form a very long saturated molecular chain (the addition polymer). ...

Isotopes Different atomic forms of the same element. Atoms with the same number of protons but a different number of neutrons Relative atomic mass The mean mass of an atom of an element, compared to 1/12th of the mass of an atom of carbon-12 Concentration= Number of moles ÷ Volume One mole 6.02×10^23 Number of moles= mass ÷ molar mass r.t.p 25 ºC 100 kPa (1 atm)

OCR A LEVEL CHEMISTRY ORGANIC SYNTHESIS WITH COMPLETE SOLUTIONS alkene undergoes what type of polymerisation - CORRECT-addition  polymerisation Alkene to alcohol - CORRECT -Electrophilic addition  conc (phosphoric) acid catalyst  steam Haloalkane to nitrile - CORRECT -nucleophilic substitution ethanolic NaCN or KCN heat Haloalkane to primary amine (also makes NH4X) - CORRECT -Nucleophilic  substitution  Excess ethanolic NH3 with no further substitution HEAT under PRESSURE ac...

What is Avagadro's constant? Correct Answer 6.02 x 10^23 number of particles in a mol Define empirical formula Correct Answer The simplest whole number ratio of atoms of each element present in a compound Define molecular formula Correct Answer The number and type of atoms of each element in a molecule What is water of crystallisation? Correct Answer Water molecules that are bonded into a crystalline structure of a compound What is the ideal gas equation? What are the units of each ...

Half life correct answers The time taken for half of a reactant to be used up Exponential decay correct answers A constant half life with the concentration halving every half life Homogeneous equilibrium correct answers Contains equilibrium species that all have the same state or phase Heterogeneous equilibrium correct answers Contains equilibrium species that have different states of phases Buffer solution correct answers A system that minimises pH changes when small amounts of an a...