Give two properties of other Group 2 compounds that decrease down the group 2 ease of thermal decomposition of carbonates solubility of carbonates insolubility of hydroxidesnitrates AW ID: 998321
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1. One Group 2 compound found in paintings is gypsum, a form of calcium sulphate. The solubility of Group 2 sulphates decreases down the group.Give two properties of other Group 2 compounds that decrease down the group. [2]ease of thermal decomposition of carbonates; solubility of carbonates;insolubility of hydroxides/nitrates; AW/ora/ two maxmust use named class of compound to gain marks
2. The calcium ion content of water can affect both the colour and texture of cooked vegetables.Hard water areas contain relatively high concentrations of calcium ions. This is caused by groundwater running over naturally occurring calcium compounds such as limestone, an impure form of calcium carbonate.(i) Describe the trend in the solubility of the Group 2 carbonates. [1](ii) The Group 2 elements form 2+ ions more easily as the group is descended and this is directly related to their reactivity.Describe and compare the reactivity of calcium and magnesium metals with water. Include a balanced equation in your answer. [5]decreases down groupGeneral reaction produces hydrogen (1); and oxide/hydroxide (1) equation; calcium more reactive (ora can be implied) (1); qualifying statement which illustrates how calcium is more reactive (1) e.g. Ca reacts more vigorously with cold water/bubbles faster One balanced equation (ignore state symbols) (1)
3. One of the main sources of magnesium metal is from magnesium ions (Mg2+) in sea water. The first stage in the production of magnesium is to mix the sea water with a slurry of calcium hydroxide.This precipitates magnesium hydroxide.(a) This reaction can be represented as follows.Mg2+(aq) + Ca(OH)2(aq) → Mg(OH)2(…..) + Ca2+(.....) Complete the state symbols on the product side of the equation. [1]s aq
4. The magnesium hydroxide produced in the equation above can be heated to produce magnesium oxide or reacted with hydrochloric acid to make magnesium chloride.Draw an electron ‘dot-cross’ diagram, in the space below, to show the ions present in magnesium chloride. Show outer electron shells only. [4] Use your knowledge of bonding in metals to suggest why metals are good conductors of electricity. [2]Delocalized/’sea’/free electrons (1); can move/mobile (1); 2
5. Carbon dioxide regulation is particularly important in coffee packaging. The CO2 is scavenged by reacting it with moist calcium oxide contained in sachets. The product is calcium carbonate, and the equation is written below. CaO(s) + CO2(g) ® CaCO3(s)The sachets contain 0.80 g of calcium oxide. Calculate the maximum volume of carbon dioxide (in cm3) that could be removed by the reaction in the equation above. [4]Give your answer to two significant figures. 1.0 dm3 = 1000 cm3; Ar: Ca, 40; O, 16. One mole of gas = 24dm3 at room temperature and pressure.Moles of CaO = 0.80/56 (1); {0.014} ecf (calculations via mass of CO2 score above mark) volume of gas = 0.80/56 × 24{0.34} (dm3) (1); → cm3 (1);sf, mark independently (1)343 on own scores 3.340 on own scores all four. 4
6. Actors in early theatre were literally ‘in the limelight’. This was because limestone was heated strongly in front of the stage illuminating the actors.The limestone (a naturally occurring form of calcium carbonate) decomposed to give calcium oxide and carbon dioxide, emitting a bright light in the process.Write a balanced equation, including state symbols, for the thermal decomposition of limestone. [3]CaCO3(s) → CaO(s) + CO2(g) LHS(1); RHS(1); appropriate states (1)
7. Complete and balance the following equation for the reaction of calcium hydroxide with hydrochloric acid. [3]Ca(OH)2(s) + …HCl(aq) → ………(aq) + ………(l)Ca(OH)2(s) + 2HCl(aq) → CaCl2(aq) + 2H2O(l)
8. Explain why bromine has a lower melting point than bromine monoflouride
9. Sulphur dioxide is often added to wine as a preservative, but it is important to get the final concentration correct. If too much is added the wine tastes of sulphur dioxide, too little and the wine goes bad. The concentration of sulphur dioxide in wine can be calculated by titrating the wine with an aqueous solution of iodine. The equation for the reaction between sulphur dioxide and iodine is shown below.SO2 (aq) + I2(aq) + 2H2O(l) → SO42–(aq) + 2I–(aq) + 4H+(aq)(i) Give the oxidation states of the iodine and sulphur before and after the reaction, by completing the following table.oxidation state of sulphur in: oxidation state of iodine in:SO2 = ......................................... I2 = .............................................SO42– = ......................................... I– = ............................................. [4]State, with a reason, whether sulphur is oxidised or reduced in the conversion of SO2 into SO42–.+4 0+6 -1Oxidised, as the (S) oxidation state has increased/ loses electrons (1) (ecf from(i) if oxidation state goes down and this is: given as reason)
10. In the event of an accident when chlorine is being transported, people living near the accident site are evacuated. Give two properties of chlorine that makes this necessary. [2] Chlorine concentrations in water are not allowed to rise above certain levels. Suggest one reason why the concentration of chlorine in water is kept very low. [1]Large amounts of chlorine are manufactured each year. Water treatment is one of the major uses for chlorine. State one other large-scale use of chlorine, apart from water treatment. [1]Volatile/gas (1); toxic to humans/causes respiratory diseases/choking gas (1)Any ONE from:Chlorine is poisonous/toxic/is a toxin/harmful/irritant (1);Damaging to respiratory system/irritating to eyes (1);Water has unacceptable smell/taste (1). Not ‘dangerous’. 1 Any ONE from:bleach/ disinfectant (1); not cleaning making PVC (1); not polymers or plastics making solvents/CFCs/insecticides/HCl (1) bromine extraction (1)
11. Bromine is made by passing chlorine through a solution derived from sea water containing bromide ions. The resulting bromine is dangerous to transport but it has several important uses.-Describe the appearance of the element bromine at room temperature. [2]-What can be deduced about the relative reactivities of bromine and chlorine from the way bromine is made? Explain your answer. [1]-Write a half-equation showing what happens to bromide ions when they are converted to molecules of the element bromine. [2]-Name the process taking place in this half-equationbrown/red/red-brown/brown-orange/red-orange (NOT orange) (1) liquid (1)chlorine is more reactive because it displaces bromine/oxidises/takes electrons away from Br– ora reason must be given 1Completely correct: 2Br– → Br2 + 2e–oxidation (ecf from a iii) NOT redox
12. One use of bromine involves making silver bromide for use in photography.Write an ionic equation, with state symbols, for the reaction between a solution of silver ions and a solution of bromide ions to form silver bromide.