A-LevelChemistryAtoms, molecules and stoichiometryFeb/Mar 2025Paper 1 Q251 Mark
Two nitrates decompose on heating according to the equations shown. 2Pb(NO3)2(s) → 2PbO(s) + 4NO2(g) + O2(g) 2NH4NO3(s) → 2N2(g) + O2(g) + 4H2O(l) One mole of each nitrate is heated separately. The gas produced in each reaction is bubbled through NaOH(aq). The volume of any gas that does not react with NaOH(aq) is then collected and measured. Which nitrate: • shows the greater percentage loss in mass • produces the greater volume of gas collected?
ANH4NO3 NH4NO3
BNH4NO3 Pb(NO3)2
CPb(NO3)2 NH4NO3
DPb(NO3)2 Pb(NO3)2
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The correct answer is A. This question tests the candidate's understanding of atoms, molecules and stoichiometry within the Chemistrysyllabus. The examiner's mark scheme requires...
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