Zadanie 1f
Explain how the rate at which the light intensity was falling after 15 minutes in the 44.8 °C run could be determined from the graph.
- Materiał graficzny
Measuring and calculating rate of reaction
Define rate as change in concentration per unit time, calculate average and instantaneous rates from the gradient or tangent of concentration, volume or mass against time graphs, and describe practical ways to follow a reaction (gas volume, mass loss, colour, conductivity).
Tę umiejętność sprawdzają 23 zadania wzorowane na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 23 Otwórz w wyszukiwarce z filtrami
Zadanie 1a
(i) Write a balanced equation for the reaction, including state symbols. (ii) Deduce what property of this reaction makes it possible to follow its rate by both methods. (iii) Magnesium carbonate was used in excess so that all of the acid would react.…
- Materiał graficzny
Zadanie 1b
In Method 1 the flask containing 25.0 cm3 of the aqueous acid was put on the balance, which was then set to zero; 0.400 g of MgCO3 was added and the reading was noted every 20 seconds until the reaction had stopped. Each point is the mean of…
- Materiał graficzny
Zadanie 20
The graph shows how the concentration of reactant X changes with time in a reaction at constant temperature. X + Z → products How does the instantaneous rate of reaction with respect to X change between 20 s and 80 s? A. Decreases 4 times B. Decreases…
- Materiał graficzny
Zadanie 1b
The sealed vessel was left for the reaction to proceed. Suggest two properties of the system, other than its colour, that could be measured to follow the progress of the reaction over time, and predict how each would change as the forward reaction proceeds.
Zadanie 3a
(i) Determine, using a suitable construction drawn on the graph, the initial rate at which CO2(g) is released, in g s−1, in the reaction with 1.20 mol dm−3 HNO3(aq). (ii) Determine the average rate of release of…
- Materiał graficzny
Zadanie 19
Which are units for rate of reaction? A. s mol−1 dm3 B. mol dm−3 min C. mol dm−3 min−1 D. mol min−1
Zadanie 19
Which of the following could be used to follow the progress of the reaction between calcium carbonate and dilute nitric acid? CaCO3(s) + 2 HNO3(aq) → Ca(NO3)2(aq) + H2O(l) + CO2(g) I. A balance recording the mass of the open flask and its contents II. A…
Zadanie 23
In a kinetics experiment, excess dilute hydrochloric acid was added to a fixed mass of marble chips (calcium carbonate), and the volume of carbon dioxide gas produced was measured over time. What is the average rate of gas production for the first 20 seconds?…
- Materiał graficzny
Zadanie 19
Equal volumes of nitrogen and hydrogen are mixed and react according to the equation below. The volumes of the two reactants are measured at intervals. N2(g) + 3 H2(g) → 2 NH3(g) Which graph shows how the volumes of the two reactants change with time? A.…
- Materiał graficzny
Zadanie 2d
The student's results are shown in the graph. (i) Calculate the average rate at which the iron(II) concentration fell in the 24 h flask during the 21 days. Include units. (ii) Before starting, the student proposed the hypothesis: "The longer a solution is left…
- Materiał graficzny
Zadanie 1c
The results in Figure 1 were processed to give Figure 2, which shows how the initial rate of reaction varies with the mass of catalyst. (i) Outline how the y-axis values in Figure 2 were obtained from the results in Figure 1. (ii) Suggest, giving a reason,…
- Materiał graficzny
Zadanie 1a
State one method that could be used to follow the progress of this reaction and explain how its measurements allow the rate, in mol dm−3 s−1, to be determined.
Zadanie 1b
The concentration of hydrogen peroxide in a reaction mixture was followed for 600 s and the results are plotted in the graph. (i) Determine the instantaneous rate of the reaction, to two significant figures, when [H2O2] = 0.160 mol dm−3.…
- Materiał graficzny
Zadanie 5a
Outline why the estimated rate calculated from the preliminary experiment is not the initial rate of the reaction.
Zadanie 5b
The student then followed the reaction with a spectrophotometer, which records the light absorbed by the mixture and so gives the concentration of the dye throughout the reaction. The graph shows [D+] against time for experiment 3. (i) Use the graph to…
- Tabela do uzupełnienia
- Materiał graficzny
Zadanie 17
Which methods could be used to determine the rate of this reaction? CaCO3(s) + 2 HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g) I. measuring the decrease in mass of the reaction mixture II. measuring the change in absorbance of light by the solution in a…
Zadanie 17
An excess of calcium carbonate lumps was added to a beaker of dilute hydrochloric acid, HCl(aq). Carbon dioxide escapes from the beaker, so the mass of the beaker and its contents was recorded against time to give curve 1. Which change could give curve…
- Materiał graficzny
Zadanie 2d
Sulfur trioxide is manufactured industrially by the oxidation of sulfur dioxide. 2 SO2(g) + O2(g) ⇌ 2 SO3(g) ΔH⊖ = −198.0 kJ mol−1 (i) Outline what is meant by dynamic equilibrium. (ii) Deduce the Kc expression for this…
- Materiał graficzny
Zadanie 6a
Suggest how the rate of this reaction could be determined experimentally.
Zadanie 29
The graph shows how the concentration of dinitrogen pentaoxide, N2O5, changes with time during its decomposition at constant temperature. What is the average rate of reaction, expressed as the rate of decrease in the concentration of N2O5, over…
- Materiał graficzny
Zadanie 1a
Heat treatment at 90 °C is used to destroy spoilage micro-organisms in pineapple juice. The concentration of vitamin C was measured over 56 days in untreated juice and in heat-treated juice from the same batch. (i) Identify the dependent variable in this…
- Materiał graficzny
Zadanie 16
The graph shows how the concentration of a reactant changes with time. What initial rate of reaction, in mol dm−3 s−1, can be determined from the graph? A. 0.1 B. 0.2 C. 0.5 D. 2.0
- Materiał graficzny