5.1. Exothermic and endothermic reactions
A subsection of Chemistry, 5070, through 5. Chemical energetics
Listing 10 of 84 questions
Aluminium carbide, Al4C3, reacts with water to form methane, CH4, and aluminium hydroxide. Construct the symbol equation for this reaction. Methane is a saturated hydrocarbon. Explain why methane is a hydrocarbon. Explain why methane is saturated. Methane reacts with chlorine in the presence of ultraviolet light. State the formulae of two products of this reaction. and Draw a dot-and-cross diagram to show the electronic configuration in a molecule of methane. Show only the outer shell electrons. The equation for the complete combustion of methane is shown. CH4 + 2O2 CO2 + 2H2O This reaction is exothermic. Explain, using ideas about bond breaking and bond making, why this reaction is exothermic. Complete the reaction pathway diagram in for the complete combustion of methane. Label the: • reactants • products • enthalpy change of the reaction, ΔH • activation energy, Ea. progress of reaction energy
5070_s24_qp_22
THEORY
2024
Paper 2, Variant 2
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Chlorine reacts with phosphorus to form phosphorus(chloride. 3Cl2 + 2P 2PCl3 The reaction is exothermic. Explain in terms of bond breaking and bond forming why the reaction is exothermic. When chlorine reacts with aqueous potassium iodide a brown solution is formed. Name the products of this reaction. and When aqueous bromine is added to potassium chloride there is no reaction. Explain why there is no reaction. Phosphorus(chloride reacts with water to form a mixture of phosphorous acid, H3PO3, and hydrochloric acid. Construct the equation for this reaction.
5070_w21_qp_21
THEORY
2021
Paper 2, Variant 1
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Questions Discovered
84