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Mathematics

Edexcel2023

x 2 y · Place the dark blue solution into a colorimeter and measure the absorbance of the solution. The table shows the absorbance of each mixture. Mixture

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Physics

Edexcel2023

0.0050 0.0010 5.00 0.00476 0.00500 0.00024 0.24

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Physics

Edexcel2021

t / ms

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Physics

Edexcel2021

The bubble chamber photograph shows tracks made by a proton and a pion. The proton and pion were both created by the decay of a lambda particle. No other particles were produced. *( a) Explain how observations and measurements from the photograph can be used to establish information about the lambda particle. (6) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. ..................................................................................................................................................................................................................................................

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Physics

Edexcel2020

The photograph shows a model racing car set. The curved parts of the track are semicircular. The car makes electrical contact with the track using metal brushes underneath the car. (a) There is a maximum speed for the car to stay on the curved part of the track. Explain why the car will slip off the curved part of the track if the car exceeds the maximum speed. (3) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. (b) The following measurements are made for a car starting at rest on a straight piece of track. distance travelled = 1.2 m time taken = 0.77 s (i) Show that the final velocity of the car is about 3 m s−1. Assume the acceleration is constant. (2) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. ..................................................................................................................................................................................................................................................

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Physics

Edexcel2020

Scientists have been studying a type of jumping spider that can jump up to six times its body length. (a) The scientists photographed a spider at 0.02s intervals, during a jump. The picture is taken from the photograph and is shown actual size. platform (i) Deduce whether the images show that the motion in the x-direction is independent of the motion in the y-direction. You should take measurements using the cross marking the centre of gravity of the spider. (4) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. ..................................................................................................................................................................................................................................................

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Physics

Edexcel2020

*P61864RA01728* Turn over PMT (ii) Show that the initial velocity of the spider at the start of the jump is about 1 m s−1. You should take measurements using the cross marking the centre of gravity of the spider. (5) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. (iii) The spider achieves this jump by extending its two back legs by 3.0 mm. Calculate the average force the spider exerts in each leg to achieve the jump. mass of spider = 150 mg (3) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. Average force = ......................................................

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Mathematics

Edexcel2019

Enthalpy change of atomisation Lattice energy of sodium of sodium –804 kJ mol–1 +107 kJ mol–1 hydride Na(s) + ½H (g)

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Mathematics

Edexcel2019

Enthalpy change of formation of sodium hydride –56 kJ mol–1 NaH(s) (i) Identify and correct the two errors in this Born-Haber cycle. (2) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (ii) Calculate the first electron affinity, in kJ mol–1, of hydrogen, using the values given in the cycle. (1)

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Mathematics

Edexcel2019

f The standard entropy change of the system, (cid:168)S , for this reaction is system –76.5 J K–1 mol–1. (i) Deduce the feasibility of this reaction at 298 K by calculating the free energy change, (cid:168)G. (2) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (ii) Calculate the temperature at which (cid:168)G = 0. (1)

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Mathematics

Edexcel2019

2 2 In an alkaline fuel cell the oxidation half-equation is H (g) + 2OH–(aq) (cid:111) 2H O(l) + 2e– 2 2 Deduce the reduction half-equation for the alkaline fuel cell. State symbols are not required. (1) (d) Lattice energies provide an indication of ionic bond strength. Which are the lattice energies of the hydrides NaH, KH and MgH ?

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Mathematics

Edexcel2019

(1) Lattice energy / kJ mol–1 Sodium hydride, NaH Potassium hydride, KH Magnesium hydride, MgH

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Mathematics

Edexcel2019

A –804 –711 –1018 B –804 –711 –2718 C –804 –911 –1018 D –804 –911 –2718 (Total for Question 8 = 8 marks)

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Mathematics

Edexcel2019

3 3 Explain how this buffer system helps to control the pH of blood when extra carbon dioxide is present due to strenuous exercise. (3) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... .....................................................................................................................................................................................................................................................................................

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Mathematics

Edexcel2019

2 3 The composition of an equilibrium mixture at 698 K and a total pressure of

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Mathematics

Edexcel2019

40 atm is shown in the table. Substance SO (g) O (g) SO (g)

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Mathematics

Edexcel2019

2 3 Number of moles /mol 0.0160 0.0120 0.772 (i) Calculate the value of K at this temperature. p Include units, if appropriate. (5) (ii) Calculate the number of sulfur dioxide molecules present in this equilibrium mixture. (1)

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Mathematics

Edexcel2019

[H O]4 D K = 2 c [H ]4

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Mathematics

Edexcel2019

(Total for Question 10 = 11 marks) TOTAL FOR PAPER = 90 MARKS

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Mathematics

Edexcel2019

The expression for the ionic product of water is K = [H+(aq)] [OH–(aq)] w The value of K at 310 K is 2.40 × 10–14 mol2 dm–6 w (i) Calculate the pH of water at 310 K. Give your answer to two decimal places. (2) (ii) Predict, with a reason, whether water is acidic, alkaline or neutral at 310 K. (2) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (iii) Predict, with a reason, the sign of the enthalpy change for the ionisation of water. (1) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (Total for Question 6 = 15 marks)

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Mathematics

Edexcel2019

*P58306A0228* DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA PMT Answer ALL questions. Some questions must be answered with a cross in a box . If you change your mind about an answer, put a line through the box and then mark your new answer with a cross .

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Mathematics

Edexcel2019

This question is about some redox reactions of chlorine, bromine and iodine. (a) An excess of aqueous potassium bromide was added to chlorine water and the solution turned orange. (i) Write an equation for this reaction. State symbols are not required. (1) (ii) Silver nitrate solution was added to the mixture in (a) and excess dilute ammonia solution was then added to the precipitate formed. Only some of the precipitate dissolved. Deduce why only some of the precipitate dissolved. (3) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (iii) Aqueous potassium bromide was added to aqueous iodine, instead of chlorine water. There was no reaction. Give a reason why no reaction occurred. (1) ..................................................................................................................................................................................................................................................................................... .....................................................................................................................................................................................................................................................................................

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Mathematics

Edexcel2019

0 cm3 of sodium hydroxide solution, of concentration 1.00 mol dm–3, was placed in a polystyrene cup. The initial temperature was measured. (i) Which piece of equipment has the smallest measurement uncertainty for the measurement of 50.0 cm3 of sodium hydroxide solution? (1) Equipment Measurement uncertainty for each reading A burette ±0.05 cm3 B 50 cm3 measuring cylinder ±1 cm3 C 25 cm3 pipette ±0.06 cm3 D 50 cm3 pipette ±0.08 cm3 (ii) 50.0 cm3 of propanoic acid solution, of concentration 1.00 mol dm–3, was added and thoroughly mixed with the sodium hydroxide solution in the polystyrene cup. The maximum temperature rise was 6.5 °C. Calculate the enthalpy change of neutralisation for propanoic acid, in kJ mol–1, giving your answer to the nearest whole number. [Assume density of the mixture = 1.00 g cm–3, specific heat capacity of the mixture = 4.18 J g–1 °C–1] (3)

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Mathematics

Edexcel2019

8 2 4 (i) Give a reason why the reaction between iodide ions and peroxodisulfate ions has a high activation energy and is therefore very slow without a catalyst. (1) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (ii) Explain, with the aid of two equations, how the iron(II) ions catalyse this reaction. State symbols are not required. (3) ..................................................................................................................................................................................................................................................................................... ..................................................................................................................................................................................................................................................................................... (b) The oxidation of sulfate(IV) ions to sulfate(VI) ions is catalysed by cobalt(II) ions in acidic solution. The role of cobalt(II) ions is similar to that of iron(II) ions in (a). Co2+ SO2– + ½O (cid:127)(cid:111) SO2–

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Mathematics

Edexcel2019

B H + C Mn 2+ D MnO –

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Mathematics

Edexcel2019

First ionisation energy of sodium +496 kJ mol–1 Na(g) + ½H (g)

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Biology

CAIE2016

(b) D. muscipula grows naturally in a small region in eastern USA. Fires that destroy much of the vegetation occur in this region. Three sites in this region where there had been fi res were identifi ed and investigated. • Site 1 had experienced a fi re 2 years before. • Site 2 had experienced a fi re 10 years before. • Site 3 had experienced a fi re 30 years before. Preliminary observations suggested that over the course of time following a fi re, the biodiversity of plants had increased. However, the abundance of Venus fl y trap plants had decreased and so had the light intensity available to them. There was also a decrease in the nitrogen that the plants absorbed from insects as a proportion of all the nitrogen they obtained from their environment. Name an ecological or statistical method to measure: (i) the abundance of D. muscipula at each site ...................................................................................................................................... [1] (ii) plant biodiversity at each site ...................................................................................................................................... [1] (iii) the strength of the relationship between light intensity and the proportion of nitrogen absorbed from insects, after taking measurements from a large number of plants. ...................................................................................................................................... [1] [Total: 8] © UCLES 2014 9700/04/SP/16 [Turn over PPMMTT

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