6.2. Rate of reaction
A subsection of Chemistry, 5070, through 6. Chemical reactions
Listing 10 of 90 questions
A student adds large pieces of zinc to dilute hydrochloric acid. The zinc is in excess. Complete the equation by adding state symbols for the products. Zn+ 2HCl ZnCl 2(….) + H2(….) shows how the volume of hydrogen changes with time as the reaction proceeds. time / s volume of hydrogen gas / cm3 Describe how the shape of the curve in shows that the rate of reaction decreases with time. Explain in terms of collision theory why the rate of reaction decreases with time. The student repeats the experiment using the same mass of powdered zinc instead of large pieces of zinc. All other conditions stay the same. Describe and explain the difference in rate of reaction when powdered zinc is used. Excess zinc is added to 16.0 cm3 of 0.400 mol / dm3 hydrochloric acid. Calculate the volume of hydrogen gas released measured at room temperature and pressure. Give your answer to two significant figures. volume of hydrogen gas = dm3 The reaction of zinc with hydrochloric acid is exothermic. Complete the reaction pathway diagram in to show: • the reactants and products • a labelled arrow for the activation energy, Ea • a labelled arrow for the enthalpy change, ΔH. energy progress of reaction Describe the observations made when: • a few drops of aqueous ammonia are added to an aqueous solution containing zinc ions • excess aqueous ammonia is added to an aqueous solution containing zinc ions. Describe how to prepare pure, dry crystals of zinc chloride after reacting excess zinc with dilute hydrochloric acid.
5070_w24_qp_22
THEORY
2024
Paper 2, Variant 2
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Questions Discovered
90