A LEVEL CHEMISTRY AQA PAPER 1 EXAM COMPREHENSIVE QUESTIONS MOST TESTED QUESTIONS AND VERIFIED SOLUTIONS 2026/100% PASS

A LEVEL CHEMISTRY AQA PAPER 1 EXAM COMPREHENSIVE QUESTIONS MOST TESTED QUESTIONS AND VERIFIED SOLUTIONS 2026/100% PASS What are the relative charges of protons, neutrons, and electrons? - -Proton +1, Neutron 0, Electron -1 Define isotope. - -Atoms of the same element with the same number of protons but different numbers of neutrons. What does the mass number represent? - -Total number of protons and neutrons. What is the principle behind TOF mass spectrometry? - -Ions are accelerated and separated by their mass-to-charge ratio. What is the trend in ionisation energy across a period? - -Increases due to increasing nuclear charge and similar shielding. Define mole. - -The amount of substance that contains 6.022 × 10²³ particles. Formula for moles using mass? - -Moles = Mass / Molar Mass Formula for moles in solution? - -Moles = Concentration × Volume (in dm³) What is the molar gas volume at RTP? - -24 dm³/mol What is atom economy? - -(Molar mass of desired product / Total molar mass of all products) × 100 What are the three main types of bonding? - -Ionic, covalent, metallic What is electronegativity? - -The ability of an atom to attract electrons in a covalent bond. Which intermolecular force is the strongest? - -Hydrogen bonding What causes London dispersion forces? - -Temporary dipoles due to electron movement NURS 283 Why do ionic compounds have high melting points? - -Strong electrostatic forces between oppositely charged ions. What is an exothermic reaction? - -A reaction that releases energy to the surroundings. Bond breaking is _______ and bond forming is _______. - -Endothermic; Exothermic Equation for enthalpy change using bond energies? - -ΔH = ∑(bonds broken) - ∑(bonds formed) What does Le Chatelier's Principle state? - -The system shifts to oppose any change in conditions. What happens to equilibrium if temperature increases in an exothermic reaction? - Shifts to the left (reactants) Define oxidation and reduction in terms of electrons. - -Oxidation = loss of electrons; Reduction = gain of electrons What is the oxidation state of oxygen in most compounds? - --2 What is a redox reaction? - -A reaction involving both reduction and oxidation. Trend in reactivity of Group 2 elements down the group? - -Increases down the group What happens to solubility of Group 2 hydroxides down the group? - -Increases What is observed when chlorine displaces bromide ions? - -Orange solution (Br₂ formed) Trend in boiling points of halogens down Group 7? - -Increases due to stronger van der Waals forces Why does halogen reactivity decrease down the group? - -Larger atomic radius and more shielding What does concordant mean in titrations? - -Two or more titres within 0.1 cm³ of each other Indicator used in acid-base titrations? - -Phenolphthalein or methyl orange What do you plot to find the rate of reaction? - -Concentration or volume vs. time Why are repeats important in experiments? - -To improve accuracy and identify anomalies NURS 283 How do you improve volume measurement accuracy? - -Use a burette or pipette instead of a measuring cylinder