Learn Extracted exam questions IGCSE Chemistry 0620 Chemistry March 2025 Question paper 22
0620 Chemistry March 2025 Question paper 22
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The diagrams show containers of gas at the same temperature. All containers have the same size. Which container contains gas at the highest pressure?
A cooling curve for a substance is shown. temperature time U V W X Y Z Which statement is correct?
Samples of four gases are released in a room at the same time. The gases are carbon dioxide, CO2, hydrogen chloride, HCl, hydrogen sulfide, H2S, and nitrogen dioxide, NO2. Which gas diffuses fastest?
Sulfur atoms can form the negative ion S2–. Three other atoms or ions are listed. ● argon, Ar ● calcium, Ca ● oxide, O2– How many of these atoms or ions have the same electronic configuration as S2–?
Element T has two isotopes, T
and T. Which statement about these isotopes is correct?
For which covalent compound does the dot-and-cross diagram correctly show the outer shell electrons? H Cl
Which row identifies the positive and the negative particles present in a giant metallic lattice? positive particles negative particles
Which formula for the named compound is correct?
The equation for the reaction of magnesium with dilute sulfuric acid is shown. Mg + H2SO4 MgSO4 + H2 [Mr: MgSO4, 120] Which mass of magnesium sulfate is formed when 12 g of magnesium completely reacts with dilute sulfuric acid?
An organic compound, Q, contains carbon, hydrogen and oxygen only. Q contains 40.0% carbon and 6.7% hydrogen by mass. What is the empirical formula of Q?
The value of the Avogadro constant is 6.02 1023. What is the total number of atoms in 2.00 mol of ammonia gas?
Three aqueous solutions, L, M and N, are electrolysed using inert electrodes. L is concentrated hydrochloric acid. M is concentrated aqueous sodium chloride. N is dilute aqueous sodium chloride. Which solutions produce a pale yellow-green gas at the anode?
Dilute sulfuric acid is electrolysed using inert electrodes. What are the ionic half-equations for the reactions that take place at each electrode? positive electrode negative electrode
Which statements about hydrogen–oxygen fuel cells are correct? They convert chemical energy into electrical energy. Hydrogen is reduced in the fuel cells. They do not produce any atmospheric pollutants.
The reaction pathway diagram for the reaction between P and Q to form R and S is shown. Which letter represents the enthalpy change for the reaction? energy progress of reaction P + Q R + S
The equation for the complete combustion of methane is shown. CH4(g) + 2O2(g) CO2(g) + 2H2O(g) The table shows some bond energies. bond bond energy in kJ / mol C–H 410 C=O 805 O=O 496 O–H 460 What is the enthalpy change for this reaction?
Which change is a physical change?
Which statements explain why increasing the temperature in a reaction involving gases increases the rate of reaction? It increases the collision frequency between the gas particles. It lowers the activation energy. It increases the kinetic energy of the gas particles. It increases the number of gas particles per unit volume.
The equation for the reaction between ammonia and oxygen is shown. 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g) H = –909 kJ / mol Which two changes to the reaction conditions will both move the position of equilibrium to the right? change 1 change 2
Mercury(II) oxide, HgO, decomposes when heated. The equation is shown. 2HgO 2Hg + O2 Why is this a reduction reaction?
Some information about two dilute acids is shown. dilute acid acid concentration in mol / dm3 pH nitric acid 0.1 1.0 propanoic acid 0.4 2.6 Three statements about the acids are listed. Nitric acid has a lower pH because it dissociates more than propanoic acid. Propanoic acid has a lower concentration of hydrogen ions than nitric acid. Propanoic acid has a higher pH because it has a higher concentration. Which statements are correct?
Element E is a metal in Group I of the Periodic Table and element G is a non-metal in Group VII. Both of these elements form oxides. Which statement about their oxides is correct?
Lead(II) sulfate is an insoluble salt. Which method is suitable for obtaining pure solid lead(II) sulfate?
The elements oxygen and sulfur are in the same group of the Periodic Table. Which statement about oxygen and sulfur is not correct?
Tennessine, Ts, is at the bottom of Group VII of the Periodic Table. What are the predicted properties of tennessine at room temperature?
An example of sacrificial protection is the fitting of zinc blocks to the outside of a ship’s steel hull. Which statement explains why zinc is used to protect the iron in the steel from rusting?
Which statement about alloys is correct?
Separate pieces of aluminium foil and copper foil are heated in air. The copper foil reacts to give a black solid. The aluminium foil does not react. Which statement explains these observations?
Which row gives the symbol equation for the formation of carbon monoxide and for the reduction of iron(III) oxide in a blast furnace? equation for the formation of carbon monoxide equation for the reduction of iron(III) oxide
A sample of river water contains a high concentration of nitrates from fertilisers. Which statements about the river water are correct? It has a boiling point of 100 °C. Its melting point is below 0 °C. It turns anhydrous cobalt(II) chloride from pink to blue. It turns anhydrous copper(II) sulfate from white to blue.
Which statements about the treatment of domestic water supplies are correct? The water undergoes sedimentation to remove dissolved solids. The water is filtered to remove insoluble solids. The water is treated with carbon to improve the taste. The water is chlorinated to decrease the pH.
An experiment to find the percentage of oxygen in 150 cm3 of polluted air is shown. water damp iron wool measuring cylinder 150 cm3 of polluted air The apparatus is left for one week. After this time, the volume of gas in the measuring cylinder is 122 cm3. What is the percentage of oxygen, to the nearest whole number, in the polluted air?
Nitrogen monoxide, NO, and carbon monoxide, CO, are both removed from the exhaust gases of a car by a catalytic converter. Which statement describes how nitrogen monoxide and carbon monoxide are removed by a catalytic converter?
Propan-1-ol is oxidised by acidified aqueous potassium manganate(VII) in a similar way to ethanol. Which compound is produced by the oxidation of propan-1-ol with acidified aqueous potassium manganate(VII)?
The structural formula of methyl propane is CH3CH(CH3)CH3. The equation represents the reaction of methyl propane with chlorine. C4H10 + Cl 2 C4H9Cl + HCl How many structural isomers with the molecular formula C4H9Cl can be formed from this reaction?
Which statements describe disadvantages of manufacturing ethanol by fermentation? The process uses a renewable resource. The process produces impure ethanol. The process requires a high temperature. The process is slow.
Nylon is made in a polymerisation reaction. Which row describes the type of polymerisation and identifies the other product of the reaction? type of polymerisation other product
Which ion forms a green precipitate with aqueous sodium hydroxide that dissolves in an excess of aqueous sodium hydroxide?
A mixture of soluble substances can be separated by paper chromatography. Each substance can be identified using its Rf value. Which formula shows how the Rf value is calculated?