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A coin is analysed by dissolving it in nitric acid. To the resulting solution an excess of aqueous ammonia is added and the mixture is filtered.A brown precipitate remains in the filter paper and a deep blue solution is obtained as the filtrate.Which metals does the coin contain? aluminium and copper, copper and iron, iron and lead, lead and zinc
An element X forms a positive ion with the electronic structure 2,8,8.What is the proton (atomic) number of X? 16, 17, 18, 19
Which two substances are elements with a giant molecular structure? diamond and graphite, diamond and sand, methane and iodine, methane and sand
Which compound has both ionic and covalent bonds? ammonium chloride, carbon dioxide, ethyl ethanoate, sodium chloride
Which statement about the numbers of particles in atoms is correct? Apart from hydrogen, most atoms contain more neutrons than protons, more protons than neutrons, more electrons than protons, more protons th
Which gas contains the same number of molecules as 9 g of water? 2 g of hydrogen, 14 g of nitrogen, 32 g of oxygen, 44 g of carbon dioxide
The mass of one mole of a chloride formed by a metal Y is 74.5 g.What is the formula of the chloride? Y3Cl, Y2Cl, YCl, YCl 2
Which reactions take place during the electrolysis of aqueous copper(II) sulfate with copper electrodes? Cu2+ + 2e– ? Cu Cu ? Cu2+ + 2e–, 4OH– ? 2H2O + O2 + 4e– Cu2+ + 2e– ? Cu, Cu ? Cu2+
The equation shows a reversible reaction.N2O4(g) 2NO2(g) The forward reaction is endothermic. Which of these changes will increase the yield of NO2? pressure decreased temperature decreased, pressure decreased temperature increased, pressure
What is not an example of oxidation? converting iron(III) salts into iron(II) salts, converting magnesium atoms into magnesium ions, diss
Which metal has a soluble carbonate, chloride and sulfate? barium, calcium, copper, potassium
Why is nickel used in the addition of hydrogen to alkenes? It increases the yield of products., It lowers the activation energy of the reaction., It makes the
Caesium, Cs, is an element in Group I of the Periodic Table.Which statements about Caesium are true?1 Caesium conducts electricity both when solid and when molten.2 Caesium reacts explosively with water.3 Caesium reacts with water and forms a solution of pH < 7. 1 and 2 only, 1 and 3 only, 2 and 3 only, 1,2and 3 only
The list shows some properties of metals. 1 Metals are good conductors of electricity. 2 Metals form ions by the loss of electrons.3 Metals have high melting points.Mercury is a metallic element. Which of these statements do not apply to mercury? 1 only, 1 and 2, 2 and 3 , 3 only
In the electrolysis of aluminium oxide to extract pure aluminium a compound called cryolite is first added to the oxide. What is the reason for adding the cryolite? to reduce the corrosion of the carbon electrodes by oxygen, to reduce energy costs, to enable the al
Iron is extracted from its ore haematite, Fe2O3, by a reduction process in the blast furnace.Which equation for reactions in the blast furnace shows the formation of the reducing agent? CaCO3 ? CaO + CO2, CaO + SiO2 ? CaSiO3, CO2 + C ? 2CO, C + O2 ? CO2
The steel bodies of cars can be protected from rusting by spraying them with zinc.Why is zinc used? Zinc does not react with acidic exhaust fumes., Zinc forms a stable compound with iron., Zinc has a
Solid Y is insoluble in water. It gives off a gas when heated and also when reacted with dilute sulfuric acid.What is Y? copper(II) carbonate, sodium carbonate, sodium nitrate, zinc oxide
What is the ionic equation for the reaction between zinc and aqueous copper(II) sulfate? Zn2+(aq) + Cu(s) ? Zn(s) + Cu2+(aq), Zn2+(aq) + SO (aq) 2 4? ? ZnSO4(s), Zn(s) + CuSO4(aq) ? ZnSO4(a
Which gas reacts with sulfuric acid to form a fertiliser? ammonia, NH3, carbon dioxide, CO2, hydrogen, H2, nitrogen, N2
In the Contact process, the sulfur trioxide formed is passed into concentrated sulfuric acid., passed into dilute sulfuric acid, passed into oleum (H2S2O7
Which gas, present in pond water, decreases in concentration during eutrophication? carbon dioxide, methane, nitrogen, oxygen
Methane is a greenhouse gas. Which process releases methane into the air? combustion of petrol, decay of vegetable matter, photosynthesis, volcanic activity
Carbon dioxide and carbon monoxide are both absorbed by sodium hydroxide., colourless., inflammable in air., lighter than air
Which hydrocarbon will burn completely in oxygen to give equal numbers of moles of carbon dioxide and water? C2H6, C3H6, C4H10, C5H12
Carbohydrates, proteins, fats and Terylene are macromolecules. Which element is found in only one of these macromolecules? carbon, hydrogen, nitrogen, oxygen