6.2. Rate of reaction
A subsection of Chemistry, 0620, through 6. Chemical reactions
Listing 10 of 319 questions
A student investigates the reaction of small pieces of zinc of the same mass and size with three different concentrations of dilute hydrochloricacid in the presence of a catalyst. The three concentrations of dilute hydrochloricacid are: ● 1.0 mol / dm3 ● 1.5 mol / dm3 ● 2.0 mol / dm3. All other conditions stay the same. Table6.1 shows the time taken for each reaction to finish. Table 6.1 concentration of hydrochloric acid in mol / dm3 time taken for the reaction to finish in s Complete Table6.1 by writing the concentrations of hydrochloricacid in the first column.  Describe the effect on the time taken for the zinc to finish reacting with 2.0 mol / dm3 hydrochloricacid with no catalyst present. All other conditions stay the same. Describe the effect on the time taken for the zinc to finish reacting with 2.0 mol / dm3 hydrochloricacid when the surface area of the zinc is increased. All other conditions stay the same. Crystals of zincchloride can be prepared by reacting excess zinc with dilute hydrochloricacid. Choose from the list, the method used to separate the unreacted zinc from the reaction mixture. Draw a circle around your chosen answer. chromatography crystallisation evaporation filtration Zincchloride is soluble in water. Choose one other compound that is soluble in water. Tick (✓) one box. calcium carbonate lead(chloride silver chloride sodium nitrate  
0620_s23_qp_31
THEORY
2023
Paper 3, Variant 1
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A student investigates the reaction of different-sized pieces of calciumcarbonate with dilute hydrochloricacid. The sizes of the pieces of calcium carbonate are: ● large ● medium ● small. All other conditions stay the same. Table6.1 shows the time taken for each reaction to finish. Table 6.1 size of pieces of calcium carbonate time taken for the reaction to finish / s Complete Table6.1 by writing the sizes of the pieces of calciumcarbonate in the first column. Describe the effect on the time taken for small pieces of calciumcarbonate to finish reacting with dilute hydrochloricacid when the temperature is increased. All other conditions stay the same. Describe the effect on the time taken for small pieces of calcium carbonate to finish reacting with dilute hydrochloric acid when the concentration of hydrochloric acid is decreased. All other conditions stay the same. Crystals of calcium chloride can be prepared by reacting excess calcium carbonate with dilute hydrochloric acid. Name the process used to separate the unreacted calciumcarbonate from the rest of the reaction mixture. Calciumcarbonate is insoluble in water. Choose one other compound that is insoluble in water. Tick (✓) one box. ammonium sulfate potassium nitrate silver chloride sodium hydroxide  
0620_s23_qp_32
THEORY
2023
Paper 3, Variant 2
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Oxygen is produced by the decomposition of aqueous hydrogenperoxide. Manganese(oxide, MnO2, is a catalyst for this reaction. State the meaning of the term catalyst. A student adds powdered manganese(oxide to aqueous hydrogenperoxide in a conical flask as shown in Fig.4.1. The mass of the conical flask and its contents is measured at regular time intervals. The mass decreases as time increases. loosely fitting cotton wool plug aqueous hydrogen peroxide powdered manganese(oxide balance State why the mass of the conical flask and its contents decreases as time increases. The rate of reaction is highest at the start of the reaction. The rate decreases and eventually becomes zero. Explain why the rate of reaction is highest at the start of the reaction. Explain why the rate of reaction eventually becomes zero. The experiment is repeated at an increased temperature. All other conditions stay the same. Explain in terms of collision theory why the rate of reaction is higher at an increased temperature. The equation for the decomposition of aqueous hydrogenperoxide, H2O2, is shown. 2H2O2→ 2H2O+ O250.0 cm3 of a 0.200 mol / dm3 solution of H2O2is used. Calculate the mass of O2 that forms. Use the following steps. ● Calculate the number of moles of H2O2 used.  mol ● Determine the number of moles of O2 produced.  mol ● Calculate the mass of O2 produced.  g  State the effect on the mass of oxygen produced if the mass of powdered manganese(oxide catalyst is increased. Oxygen can also be produced by the decomposition of mercury(oxide, HgO. The only products of this decomposition are mercury and oxygen. Write a symbol equation for this decomposition. 
0620_s23_qp_41
THEORY
2023
Paper 4, Variant 1
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