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AQA A-Level Chemistry (new spec) 1.1 Atomic Structure Questions and Answers Number of neutrons is worked out by... Subtracting the atomic number from the mass number Define isotopes Atoms of the same element with the same number of protons but a different amount of neutrons Isotopes have similar chemical properties because... they have the same electron configuration Isotopes have varying physical properties because... they have different masses Define ions A ch...

AQA A-Level Chemistry Aromatic Chemistry Questions and Answer State the three problems with Kekule's structure 1. C=C bonds are actually all the same length rather than the predicted 3 long single bonds and 3 short double bonds. 2. Benzene doesn't undergo addition reactions which you would expect trienes to readily undergo 3. Enthalpy change of hydrogenation is 152 kJ mol-1 less than expected. What are arenes? Hydrocarbons based on benzene Why do arenes have high melting...

AQA A Level Chemistry – Equilibria Questions and Answers What are the two characteristics of a system is in dynamic equilibrium? 1. both forward and backward reactions proceed at equal rate 2. the concentrations of the reactants and products remain constant What is Le Chatlier's principle used for? It is a tool to help predict the effects of temp, pressure and concentration on the position of equilibrium What happens to the position of equilibrium if temperature is increas...

Topic 1. Edexcel Chemistry A level Questions and Answers What is atomic number? -The number of protons in the nucleus of an atom of an element. -All atoms of the same element have the same number of protons. What is the mass number? The total number of protons and neutrons in the nucleus of an atom of an element. What is an isotope? - Atoms of an element with the same number of protons but a different number of neutrons. - Same proton number but different mass number. ...

A-Level Chemistry Bond Angles and Shape Questions and Answers 2 electron pairs around the central atom Shape: Linear Bond Angle: 180 Example: Carbon Dioxide (CO2) 3 electron pairs around the central atom Shape: Trigonal planar Bond Angle: 120 Example: Boron Trifluoride (BF3) 4 electron pairs around the central atom Shape: Tetrahedral Bond Angle: 109.5 Example: Methane (CH4) 5 electron pairs around the central atom Shape: Trigonal bipyramid Bond Angle: 120 and 90 ...

Edexcel A-Level Chemistry Transition Metal Colours Questions and Answers What colours are MnO4- [+7] , MnO42- [+6], and Mn2+ [+2], in an aqueous complex? Purple, Green and Pale Pink respectively What colours are Ti3+ , Ti2+ in an aqueous complex Purple and Violet respectively What colours are VO2+ , VO2+ , V3+ and V2+ in an aqueous complex Yellow, Blue, Green, and Violet respectively What colours are CrO72- and Cr3+ in an aqueous complex Orange and green respectively ...

Common Questions A level chemistry unit 1 Questions and Answer Define the term relative atomic mass of an element. (2) mean mass of an atom of an element divided by one twelfth the mass of a carbon-12 atom State how the molecular mass of a covalent compound is obtained from its mass spectrum (1) the highest m/z value Explain why isotopes have identical chemical properties (1) they have the same electron configuration State what is meant by the term isotopes (1) atoms of...

A Level Chemistry Periodicity Questions and Answers Define group A vertical column. Elements in a group have similar chemical properties as they have the same number of outer shell electrons Define periodicity A repeating pattern of properties shown across different periods What is the s-block? Groups 1 and 2 What is the p-block? Groups 3-8 What is the d-block? Transition elements What is the f block? Lanthanides and actinides Define first ionisat...

AQA A-LEVEL CHEMISTRY Periodicity Questions and Answers BLOCKS What is the s, p, d and f block on the periodic table? S - 1,2 P - 3,4,5,6,7,8 D - Transition Metals F - Bottom. According to whatever the highest energy level is. ATOMIC RADIUS Why does the atomic radius decrease across the period? The increased number of protons pulls the electrons closer to it with minimal change in shielding to prevent that from ocurring. FIRST IONISATION ENERGY What is the genera...

Edexcel A level chemistry practicals Questions and Answers 8)b. measure enthalpy change of decomposition of KHCO3- key points and errors This practical combines two neutralisation reactions: 1. K2CO3 + 2HCL --> 2KCL + H2O +CO2 2. 2KHCO3 + 2HCL --> 2KCL +2H20 +2CO2 The desired reaction is: 2KHCO3 --> 2K2CO3 +CO2+ H2O use Q=mcΔT and ΔH=-Q/n Errors- assume specific heat capacity is the same as water. Heat lost to surroundings. Polystyrene is more insulating than glass so ...