ZXTape! 0Created with Ramsoft MakeTZXÊchem3 Ê4 ÿ3(= Ì4ÿ ê J J WARREN 1982 ñs=0:éc(10 ) %ën=1Ì10 :ñc(n)=0:ón ('ñb$=" " <ñn=1:ñs=0 P-û:ç5:õÚ6;Ù7;" ";Ù0;" Educational Software " UNõ¬12 ,0;" Redox, Electrolysis and the"'" Activity series." ZŸõ¬17,0;Ú6;"  1982 J J Warren BSc ARCS Cert Ed " d@å:ëg=1Ì5:ãs$:ëm=0Ì7:ãa:ôÀs$+m,a:óm:óg nlä"a",0,0,0,255ÿ,255ÿ,0,0,0,"b",0,0,0,127,127,0,0,0,"c",0,24,12 ,254þ,254þ,12 ,24,0,"d",0,0,0,60<,4,60<,32 ,60<,"e",0,0,0,60<,4,28,4,60< s+ñl$="" xí21004:ç7:û }·õ"Do you want:";¬5,3;"1. A revision tutorial"''" 2. A simple test"''" 3. A copy of the questions"'" on your printer?";¬19,0;"Type 1, 2 or 3." ‚ú¦É""Ëì130‚ „ú¦=""Ëì132„ †ñm$=¦ ‡qúm$="3"Ëà''''" Redox, Electrolysis and the"'" Activity Series."''"________________________________"'''' ˆ!úm$="1"Åm$="2"Åm$="3"Ëì140Œ Š ì130‚ Œì3750¦+500ô*n –û ›ñr$="" úm$="4"Æc(n)=1Ëì8204  *õ"Question ";n''"First Statement"'' ´í3500¬ +500ô*n ¾+õ¬8,0;"Second statement"'' Òí3550Þ +500ô*n Ôúm$="3"Ëÿ:ì8204 Ü2õ¬19,0;"Is the first statement true?" æ í1000è ú ñf$="true " úi$="n"Ëñ f$="false" 7õ¬19,0;"Is the second statement true?" " í1000è 6 ñs$="true " @úi$="n"Ëñs$="false" Oõ¬19,0;b$ T"úf$É"true "Ås$É"true "Ëì420¤ ^Zõ¬18,0;"Is the 2nd statement a correct explanation of the 1st? " | í1000è ñr$="correct " šúi$="n"Ëñr$="not correct" ¤û ©úm$="2"Ëì810* ®úf$=o$Ëõ"Well done." ¸úf$Éo$Ëõ"Wrong." Ìõ'l$ Ö7Ú6:õ" The first statement was ";o$;" ":Ú7 àõl$'' ô$úo$="true "Ëí3500¬ +500ô*n þ ñx=0  í2000Ð û ús$=t$Ëõ"Well done." &ús$Ét$Ëõ"Wrong." :õ'l$ D7Ú6:õ" The second statement was ";t$;" ":Ú7 Nõl$'' b$út$="true "Ëí3550Þ +500ô*n l ñx=1 v í2000Ð {û €úe$=""Ëì800  ‚ ñx=2 …%úr$É""Ær$Ée$Ëõ"You were wrong. "''l$ Š$úr$=e$Ëõ"Good, you were right."''l$ ”úe$É"correct "Ëì740ä žSõ"Both statements are true, and the 2nd is a correct explanationof the 1st."'l$' ¼í3500¬ +500ô*n Æõ'"because"'' Ðí3550Þ +500ô*n Õ í21004 Ú í800  óõ'" The fact that "'' øí3550Þ +500ô*n "õ'" is not the reason why "''  í3500¬ +500ô*n  í2000Ð  û *!úf$=o$Æs$=t$Ær$=e$Ëñc(n)=1 4 ñn=n+1 >ún<11 Ëì140Œ ?úm$="3"Åm$="4"Ëì960À @ën=1Ì10 B ñs=s+c(n) Dón Haõ("Excellent."Æs=10 )+("Very good."Æs=9 )+("Well done."Æs=8)+("Good."Æs=7) pDús=5Ås=6Ëõ"You need to spend more time on this topic." zOús<5Ëõ"Your very low score indicates a poor understanding of this topic" Ž:õ'"You correctly answered ";s;" out"'"of 10 questions."'' ¬iús<5Ëõ"You need to read through your notes and text-book again,"'"and then re-run this program." ®í21004:û ¶úm$="1"Ås=10 Ëì960À ¸Kõ"Do you want to go through the questions in which you made"'"mistakes?" ¹ í1000è ºúi$="n"Ëì960À »ñm$="4" ¼ ñn=1 ½ ì140Œ Àû Ê*õ"Do you want to run the program again?" Ô í1000è Ùû Þ úi$="n"Ëâ ã ì10 ò6õ¬21,0;"Type y or n. " ÷ú¦É""Ëì1015÷ üú¦=""Ëì1020ü ñi$=¦ úi$="y"Åi$="n"Ëþ ,õ¬21,0;" Please type y Ån." $ ì1015÷ V õ"Well done, you were right.":þ æõ"No, You were wrong.":þ ÐTõ¬20,0;"Type e for explanation/comment otherwise press the ENTER key." Úú¦É""Ëì2010Ú äú¦=""Ëì2020ä îú¯¦=13 Ëþ óú¦É"e"Ëì2010Ú øû:õl$ Núx=0Æo$="true "Åx=1Æt$="true "Ëí3500¬ +500ô*n+502*x  õl$'' #í3600+500ô*n+502*x  í21004 *þ 46õ¬21,0;"Press the ENTER key to continue." >ú¦É""Ëì2110> Hú¦=""Ëì2120H Mú¯¦É13 Ëì21004 Rþ  2õ"Elemental chlorine oxidises"'"iron (II) ions":þ ÒAõ"Chlorine molecules can take"'"electrons from iron (II) ions":þ +õ"Oxidation is the process by"'"which atoms, molecules or ions lose electrons."''"When an iron (II) ion loses one electron, an iron (III) ion is formed."''" 2+ 3+ -"'" Fe ‘’ Fe + e"''"The electrons are taken by the chlorine, which acts as an"'"oxidising agent.":þ 6½õ­12 ;"- -"'" Cl + 2e ‘’ 2Cl"'" 2"'"  ^ "''"These electrons are taken from iron (II) ions."''"The chlorine molecules are"'"reduced to chloride ions.":þ š5ño$="true ":ñt$="true ":ñe$="correct ":ì150– ”Jõ"Metals high in the activity"'"series have good reducing"'"properties":þ ÆRõ"Reduction is the process by"'"which atoms, molecules or ions gain electrons":þ ø>õ"A reducing agent gives electronsto the substance which is being reduced."''"Metals high in the activity"'"series, such as potassium,"'"readily give up electrons, and"'"form positive ions."''"They therefore act as reducing agents, and are themselves"'"oxidised."'" + -"'"e.g. K ‘’ K + e":þ *Bõ"This is the modern definition ofreduction. For example, when"'"potassium is burnt in oxygen, the oxygen gains electrons and is therefore reduced."'­11 ;"- 2-"'" O + 4e ‘’ 2O"'" 2"''"The electrons come from the"'"potassium, which is oxidised."'" + -"'" 4K ‘’ 4K + 4e":þ \×õ"The metals which are readily"'"oxidised (have good reducing"'"properties) are placed at the top of the activity series."''"This is simply the way in which chemists have agreed to arrange the activity series.":þ Ž5ño$="true ":ñt$="true ":ñe$="not correct":ì150– ˆ[õ"The conversion of sulphite ions to sulphate ions is neither"'"oxidation nor reduction":þ ºRõ"The charge on the sulphite ion is the same as the charge on thesulphate ion":þ ìJõ"The conversion of sulphite ions to sulphate ions is oxidation. The partial ionic equation is:"''" 2- 2- + -"'"SO + H O ‘’ SO +2H + 2e"'" 3 2 4"''"The sulphite ions give up"'"electrons and gain oxygen."''"Oxidation is electron loss."''"Oxidation is the gain of oxygen.":þ tõ"Both ions have a double negativecharge:"'''" 2-"," 2-"'" SO","SO"'" 3"," 4"''"sulphite sulphate":þ ‚*ño$="false":ñt$="true ":ñe$="":ì150– |Rõ"The change from ethene (CH“=CH“)to ethane (CH”CH”) is classifiedas reduction":þ ®`õ"Reduction can be defined as a process involving the addition of hydrogen to a substance":þ àñõ"Addition of hydrogen has taken place, therefore the change is reduction."''"CH =CH + H ‘’ CH CH"'" 2 2 2 3 3"''"The reaction takes place when ethene gas and hydrogen are"'"passed over a heated nickel"'"catalyst.":þ tõ"Other definitions include:"''"Reduction is the loss of oxygen"''"Reduction is the gain of"'"electrons.":þ v5ño$="true ":ñt$="true ":ñe$="correct ":ì150– pUõ"When copper (II) oxide is heatedin a stream of hydrogen, copper metal is formed":þ ¢+õ"Copper (II) oxide is a reducing agent":þ ÔÕõ"The black copper oxide is"'"reduced to a reddish-brown"'"powder. This is a very fine formof copper metal."''"The hydrogen is oxidised to"'"water."''" CuO + H ‘’ Cu + H O"'" 2 2":þ íõ"CuO + H ‘’ Cu + H O"'" 2 2"''"Copper (II) oxide is reduced to copper metal, and the hydrogen is oxidised to water."''"The copper (II) oxide has acted as an oxidising agent in this reaction":þ j*ño$="true ":ñt$="false":ñe$="":ì150– dNõ"When zinc reacts with iodine to form zinc iodide, the iodine is oxidised":þ –Rõ"The change from molecular iodineto iodide ions involves the gainof electrons":þ Èýõ"When zinc reacts with iodine to form zinc iodide,"''"The zinc is oxidised (loses"'"electrons)"'" 2+ -"'" Zn ‘’ Zn + 2e"''"The iodine is reduced (gains"'"electrons)"'" - -"'" I + 2e ‘’ 2I"'" 2" Ò–í21004:û:õ"The overall equation for the"'"reaction is:"''" Zn + I ‘’ ZnI"'" 2 2"''"Zinc iodide is an ionic"'"compound.":þ úÊõ'" - -"'" I + 2e ‘’ 2I"'" 2"''"In the reaction between iodine and zinc, the iodine molecules gain electrons from the zinc"'"atoms, and are reduced to iodideions.":þ ^*ño$="false":ñt$="true ":ñe$="":ì150– XRõ"Silver metal reacts with dilute hydrochloric acid to liberate hydrogen gas":þ ŠIõ"Silver is above hydrogen in the activity (electrochemical)"'"series":þ ¼¦õ"Silver is too unreactive a metalto liberate hydrogen gas from acids."''"It will dissolve in oxidising acids, e.g. in nitric acid, but no hydrogen is formed.":þ î¥õ"Potassium  The activity series Sodium  lists the metals in Lithium  order of decreasing Calcium  reactivity. Magnesium  Aluminium  Copper and silver Zinc  are both below Iron  hydrogen in the Lead  activity series. Hydrogen  Neither can liberateCopper  hydrogen from acids.Silver ":þ R*ño$="false":ñt$="false":ñe$="":ì150– LCõ"Zinc metal will displace copper from copper sulphate solution":þ ~3õ"Zinc is below copper in the"'"activity series":þ °ûõ"Zinc is the more reactive metal,and is oxidised to give"'"zinc (II) ions."''" 2+ -"'" Zn ‘’ Zn + 2e"''"The electrons from the zinc"'"reduce the copper (II) ions to copper metal."''" 2+ -"'" Cu + 2e ‘’ Cu":þ âïõ"Zinc is above copper in the"'"activity series."''" Potassium "'" Sodium "'" Lithium "'" Calcium "'" Magnesium "'" Aluminium "'" Zinc "'" Iron "'" Lead "'" Hydrogen "'" Copper "'" Silver " ìÙí21004:û:õ"Metals higher in the activity"'"series can displace metals lowerin the series from solutions of their salts."''"For example:"''" 2+ 2+"'"Zn(s)+ Cu (aq) ‘’ Zn (aq)+ Cu(s)":þ êõ"The activity series is based on the relative reactivities of themetals."''"One of the reasons for zinc"'"being above copper in the"'"activity series is the fact thatzinc will displace copper from aqueous solutions of its salts.":þ F*ño$="true ":ñt$="false":ñe$="":ì150– @]õ"When molten lead bromide is"'"electrolysed, a brown vapour"'"comes off from the cathode":þ r@õ"During electrolysis reduction takes place at the cathode":þ ¤6õ"Bromine is formed at the anode when molten lead bromide is"'"electrolysed. The bromine can beseen as a brown vapour."''"The molten electrolyte contains lead ions and bromide ions."''"The anions (negative bromide"'"ions) are attracted to the anodeand lose electrons. They undergoelectrolytic oxidation." ®Iõ'" - -"'" 2Br ‘’ Br + 2e"'" 2":þ Öìõ"Positively charged ions(cations)are attracted to the cathode."''"They gain electrons from the"'"cathode, and so are reduced."''"For example, lead ions gain"'"electrons to form lead atoms."''" 2+ -"'" Pb + 2e ‘’ Pb":þ :*ño$="false":ñt$="true ":ñe$="":ì150– !4{õ"When copper sulphate solution iselectrolysed using graphite"'"electrodes, hydroxide ions are discharged at the anode":þ !fmõ"Hydroxide ions have a single"'"negative charge, whereas"'"sulphate ions have a double"'"negative charge":þ !˜Gõ"The anions present are hydroxideions (from the ionisation of"'"water) and sulphate ions."'"The hydroxide ions are"'"discharged to give oxygen gas:"''" - -"'"4OH ‘’ O + 2H O + 4e"'" 2 2"''"Some carbon dioxide is formed due to oxidation of the graphiteanode by the oxygen.":þ !Ê^õ" -"," 2-"'" OH","SO"'," 4"''"Hydroxide Sulphate"' " ion ion":þ !üzõ"Although the hydroxide ion has avery much lower concentration than the sulphate ion in copper sulphate solution, The hydroxideions are selectively discharged."''"However, there are examples in which ions with higher charges are discharged in preference to ions with a lower charge."''"There is no simple reason why some ions are discharged in"'"preference to others.":þ ".5ño$="true ":ñt$="true ":ñe$="not correct":ì150– sî çdída<ƒ5 B SeL$X ùchem4 ¶4 ë3GÛ`¸4ÿ ê J J WARREN 1982 ñs=0:éc(10 ) %ën=1Ì10 :ñc(n)=0:ón ('ñb$=" " 2iå:ëg=1Ì5:ãs$:ëm=0Ì7:ãa:ôÀs$+m,a:óm:óg:ñl$="" 7qä"a",0,0,0,255ÿ,255ÿ,0,0,0,"b",0,0,0,127,127,0,0,0,"c",0,24,12 ,254þ,254þ,12 ,24,0,"d",0,0,63?,0,63?,63?,24,12 ,"e",16,8,252ü,0,252ü,252ü,0,0 <ñn=1:ñs=0 P-û:ç5:õÚ6;Ù7;" ";Ù0;" Educational Software " U1õ¬12 ,4;"Acids, Bases and Salts." ZŸõ¬17,0;Ú6;"  1982 J J Warren BSc ARCS Cert Ed " xí21004:ç7:û }·õ"Do you want:";¬5,3;"1. A revision tutorial"''" 2. A simple test"''" 3. A copy of the questions"'" on your printer?";¬19,0;"Type 1, 2 or 3." ‚ú¦É""Ëì130‚ „ú¦=""Ëì132„ †ñm$=¦ ‡Rúm$="3"Ëà''''" Acids, Bases and Salts."''"________________________________"'''' ˆ!úm$="1"Åm$="2"Åm$="3"Ëì140Œ Š ì130‚ Œì3750¦+500ô*n –û ›ñr$="" úm$="4"Æc(n)=1Ëì8204  *õ"Question ";n''"First Statement"'' ´í3500¬ +500ô*n ¾+õ¬8,0;"Second statement"'' Òí3550Þ +500ô*n Ôúm$="3"Ëÿ:ì8204 Ü2õ¬19,0;"Is the first statement true?" æ í1000è ú ñf$="true " úi$="n"Ëñ f$="false" 7õ¬19,0;"Is the second statement true?" " í1000è 6 ñs$="true " @úi$="n"Ëñs$="false" Oõ¬19,0;b$ T"úf$É"true "Ås$É"true "Ëì420¤ ^Zõ¬18,0;"Is the 2nd statement a correct explanation of the 1st? " | í1000è ñr$="correct " šúi$="n"Ëñr$="not correct" ¤û ©úm$="2"Ëì810* ®%úf$=o$Ëõ"Well done, you were right." ¸!úf$Éo$Ëõ"Your answer was wrong." Ìõ'l$ Ö7Ú6:õ" The first statement was ";o$;" ":Ú7 àõl$'' ô$úo$="true "Ëí3500¬ +500ô*n þ ñx=0  í2000Ð û )ús$=t$Ëõ"Good, your answer was correct." &ús$Ét$Ëõ"You were wrong." :õ'l$ D7Ú6:õ" The second statement was ";t$;" ":Ú7 Nõl$'' b$út$="true "Ëí3550Þ +500ô*n l ñx=1 v í2000Ð {û €úe$=""Ëì800  ‚ ñx=2 …2úr$É""Ær$Ée$Ëõ"Unfortunately you were wrong."''l$ Š$úr$=e$Ëõ"Good, you were right."''l$ ”úe$É"correct "Ëì740ä žSõ"Both statements are true, and the 2nd is a correct explanationof the 1st."'l$' ¼í3500¬ +500ô*n Æõ'"because"'' Ðí3550Þ +500ô*n Õ í21004 Ú í800  óõ'" The fact that "'' øí3550Þ +500ô*n "õ'" is not the reason why "''  í3500¬ +500ô*n  í2000Ð  û *!úf$=o$Æs$=t$Ær$=e$Ëñc(n)=1 4 ñn=n+1 >ún<11 Ëì140Œ ?úm$="3"Åm$="4"Ëì960À @ën=1Ì10 B ñs=s+c(n) Dón Haõ("Excellent."Æs=10 )+("Very good."Æs=9 )+("Well done."Æs=8)+("Good."Æs=7) pDús=5Ås=6Ëõ"You need to spend more time on this topic." zOús<5Ëõ"Your very low score indicates a poor understanding of this topic" Ž:õ'"You correctly answered ";s;" out"'"of 10 questions."'' ¬iús<5Ëõ"You need to read through your notes and text-book again,"'"and then re-run this program." ®í21004:û ¶úm$="1"Ås=10 Ëì960À ¸Kõ"Do you want to go through the questions in which you made"'"mistakes?" ¹ í1000è ºúi$="n"Ëì960À »ñm$="4" ¼ ñn=1 ½ ì140Œ Àû Ê*õ"Do you want to run the program again?" Ô í1000è Ùû Þ úi$="n"Ëâ ã ì10 ò6õ¬21,0;"Type y or n. " ÷ú¦É""Ëì1015÷ üú¦=""Ëì1020ü ñi$=¦ úi$="y"Åi$="n"Ëþ ,õ¬21,0;" Please type y Ån." $ ì1015÷ V õ"Well done, you were right.":þ æõ"No, You were wrong.":þ ÐTõ¬20,0;"Type e for explanation/comment otherwise press the ENTER key." Úú¦É""Ëì2010Ú äú¦=""Ëì2020ä îú¯¦=13 Ëþ óú¦É"e"Ëì2010Ú øû:õl$ Núx=0Æo$="true "Åx=1Æt$="true "Ëí3500¬ +500ô*n+502*x  õl$'' #í3600+500ô*n+502*x  í21004 *þ 46õ¬21,0;"Press the ENTER key to continue." >ú¦É""Ëì2110> Hú¦=""Ëì2120H Mú¯¦É13 Ëì21004 Rþ  õ"All acids contain oxygen":þ ÒHõ"All acids may be formed by"'"dissolving non-metal oxides in water":þ ºõ"The majority of acids do containoxygen, e.g."''" HNO H CO H SO"'" 3 2 3 2 4"''"A few acids do not contain"'"oxygen. Hydrochloric acid, HCl, is one example.":þ 6<õ"Many acids are formed when non- metal oxides are dissolved in water."'"E.g., sulphur trioxide dissolves to give sulphuric acid:"''" H O + SO ‘’ H SO"'" 2 3 2 4"''"However, it is not true of all acids."''"Hydrochloric acid is made by"'"dissolving hydrogen chloride"'"gas (HCl) in water.":þ hµõ"You cannot give a reason for a definition or commonly accepted term."''"Scientists have simply agreed to use the term in that way so that they can understand each other.":þ š*ño$="false":ñt$="false":ñe$="":ì150– ”Cõ"Acids react with sodium"'"carbonate giving a colourless"'"gas":þ Æ<õ"Acids contain hydrogen which maybe replaced by a metal":þ ø»õ"The colourless gas is carbon dioxide."''"  Acid + Metal Carbonate"''"  gives "''"Salt + Carbon Dioxide + Water "''"This reaction is characteristic of acids.":þ *õ"This is sometimes used as the"'"definition of an acid."''"An acid is a proton (hydrogen"'"ion) donor, and so must contain hydrogen."''"When an acid reacts with a base the hydrogen ions are replaced by metal ions (or other cations such as the ammonium ion) to"'"give a salt.":þ \ßõ"The colourless gas formed when acids react with sodium"'"carbonate is carbon dioxide."''"For example, if the acid is"'"hydrochloric acid, then:"''"Na CO + 2HCl ‘’ 2NaCl + CO + H O 2 3 2 2":þ Ž5ño$="true ":ñt$="true ":ñe$="not correct":ì150– ˆDõ"A solution of sulphur dioxide in water turns red litmus blue":þ ºBõ"Sulphur dioxide dissolves in"'"water to form sulphurous acid":þ ì„õ"Sulphur dioxide is an acidic"'"oxide."''"It dissolves in water to give sulphurous acid."'''" Acids turn blue litmus red.":þ öõ'" H O + SO ‘’ H SO"'" 2 2 2 3"''"The sulphurous acid ionises to give hydrogen and sulphite ions:"'',"+ 2-"'" H SO ‘’ 2H + SO"'" 2 3 3"''"The hydrogen ions make the"'"solution acidic.":þ ‚*ño$="false":ñt$="true ":ñe$="":ì150– |Aõ"Ethanoic (acetic) acid in"'"aqueous solution is a weak acid":þ ®@õ"Ethanoic acid dissolves in waterto give a solution of pH 7":þ àóõ"A weak acid is one which is onlypartly ionised."''"In water, most of the ethanoic acid is present as molecules."'"Only a small proportion is"'"ionised."''," - +"'" CH CO H “” CH CO + H"'" 3 2 3 2":þ Úõ"pH 7 corresponds to a neutral solution."''"Acids in aqueous solution give apH of less than 7."''''"The pH of dilute ethanoic acid solution is about 3."''"(The exact value depends upon the concentration).":þ v*ño$="true ":ñt$="false":ñe$="":ì150– p*õ"Hydrochloric acid is a strong acid":þ ¢Nõ"Hydrochloric acid is formed by dissolving hydrogen chloride gasin water":þ ÔÚõ"A strong acid is highly ionised,and so gives a high"'"concentration of hydrogen ions."''"Hydrochloric acid consists of hydrogen ions and chloride ions in aqueous solution."'',"+ -"'" HCl ‘’ H + Cl" Þ í21004:û:õ"The solution of hydrogen"'"chloride in water is more fully"'"represented by:"'''," + -"'"HCl(g)+H O(l)‘’H O (aq)+Cl (aq) 2 3"'''" +"'"H O is the hydrated hydrogen 3 ion. It is called the hydronium ion.":þ ¯õ"Hydrogen chloride is very"'"soluble in water."''"When it dissolves the molecules split up to form ions. The ions are hydrated.":í21004:û:õ"The hydrogen ions (protons) are bonded to water molecules"'"forming hydronium ions:"''''" H + The oxygen atom of ^ the water molecule H-O uses a lone pair of | electrons to form a H dative bond to the hydrogen ion.":þ 8Ãõ"There is no direct connection between solubility and the"'"strength of an acid."''"Sulphur dioxide is very soluble in water. Sulphurous acid is"'"formed, but this is a rather"'"weak acid.":þ j5ño$="true ":ñt$="true ":ñe$="not correct":ì150– dKõ"When ammonia gas is dissolved inwater it forms an alkaline"'"solution":þ –8õ"Ammonia reacts with water to"'"form hydroxide ions":þ Ȫõ"Ammonia is a base and so gives asolution with a pH greater than 7."''"Ammonia solution turns red"'"litmus blue, thus showing that the solution is alkaline.":þ úüõ"Ammonia acts as a base by"'"accepting a hydrogen ion from a water molecule."''"This yields ammonium and"'"hydroxide ions:"''," + -"'"NH + H O “” NH + OH 3 2 4"''"The hydroxide ions make the"'"solution alkaline.":þ ^5ño$="true ":ñt$="true ":ñe$="correct ":ì150– XYõ"Black copper oxide dissolves in dilute sulphuric acid to form a colourless solution":þ Š@õ"Metal sulphates always give"'"colourless aqueous solutions":þ ¼õ"Black copper oxide does dissolvein dilute sulphuric acid, but"'"the solution formed is blue."'''"The products of the reaction arecopper sulphate(blue) and water."'''"H SO + CuO ‘’ CuSO + H O 2 4 4 2"''"Acid + Base ‘’ Salt + Water":þ î,õ"The colour of solutions of metalsulphates depends on the colour of the metal ion, as the"'"sulphate ion is colourless."''"The majority of common metal"'"ions are colourless in solution.Exceptions include:"''" Copper (2+) Blue"'" Iron (2+) Pale green"'" Iron (3+) Brownish-yellow":þ R*ño$="false":ñt$="false":ñe$="":ì150– L5õ"Carbon dioxide is classified as an acidic oxide":þ ~+õ"Carbon dioxide turns lime-water milky":þ °"õ"Carbon dioxide dissolves in"'"water giving carbonic acid:"''" H O + CO ‘’ H CO "'" 2 2 2 3"''"Carbon dioxide also reacts with and neutralises bases, for"'"example, with sodium hydroxide solution:"''" CO + 2NaOH ‘’ Na CO + H O 2 2 3 2":þ âõ"Lime-water is a saturated"'"solution of calcium hydroxide."''"This reacts with carbon dioxide to give calcium carbonate."''"Ca(OH) + CO ‘’ CaCO + H O 2 2 3 2"''"The calcium carbonate formed is insoluble in water, and forms a milky-white suspension.":þ õ"Carbon dioxide is classified as an acidic oxide because it will react with and neutralise bases."''"The reaction with lime-water is just one example of this"'"behaviour."''"Note that other acidic oxides may react with lime-water, but they do not turn it milky." :þ F5ño$="true ":ñt$="true ":ñe$="not correct":ì150– @1õ"Potassium hydrogensulphate is a normal salt":þ r}õ"Potassium hydrogensulphate is formed when equal numbers of"'"moles of potassium hydroxide andsulphuric acid are mixed":þ ¤1õ"A normal salt is formed when allof the hydrogens of an acid arereplaced by metal ions."''"Potassium hydrogensulphate is"'"an acid salt."'''" H SO KHSO K SO"'" 2 4 4 2 4"''" Acid Acid Normal salt  salt ":þ ÖÞõ"H SO + KOH ‘’ KHSO + H O "'" 2 4 4 2"''"When one mole of potassium"'"hydroxide reacts with one mole of sulphuric acid, only one of the hydrogens of the acid is"'"replaced by potassium ions.":þ :*ño$="false":ñt$="true ":ñe$="":ì150– !4bõ"Lead iodide can be prepared by mixing cold solutions of lead nitrate and potassium iodide":þ !f/õ"Lead iodide is quite soluble in hot water":þ !˜õ"When the two colourless"'"solutions are mixed, bright"'"yellow crystals of lead iodide are formed."''"Pb(NO ) + 2KI ‘’ PbI + 2KNO 3 2 2 3"''"The precipitated lead iodide canbe separated from the potassium nitrate solution by filtration.":þ !ÊÕõ"Lead iodide is almost insoluble in cold water, but does dissolvein hot water to give a"'"colourless solution."''"When this solution is cooled, the lead iodide crystallises outas glittering yellow crystals.":þ !üºõ"Lead iodide can be prepared by mixing cold solutions of lead nitrate and potassium iodide because it is insoluble in cold water, and not because it is"'"soluble in hot water.":þ ".5ño$="true ":ñt$="true ":ñe$="not correct":ì150– sî ç2í2aƒ5 B SeL$ê