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AQA A1 group 2 and 7
AQA group 2 and 7
Question | Answer |
---|---|
Write the simplest IONIC equation for the precipitation of Magnesium Hydroxide | Mg+2 + 2 OH- Mg(OH)2; Check formula of the precipitate; unswap; the ions go as reactants; balance the equation; check states symbols (precipitate=s) |
Write the simplest IONIC equation for the reaction of Silver Nitrate with a solution containing Chloride ions | Ag+1 + Cl- -->AgCl; FIRST Silver Chloride PRECIPITATE is made: treat this as a precipitation reaction; and/or SNAP ions do not show in ionic equation; Check formula precipitate; unswap; the ions go as reactants; balance the equation; check states symbols |
Write the simplest IONIC equation for the reaction of Barium Chloride with Sodium Sulfate | Ba+2 + SO4-2- -->Ba(SO4); FIRST: Barium Sulfate PRECIPITATE is made: treat this as a precipitation reaction; and/or SNAP ions do not show in ionic equation; Check formula precipitate; unswap; ions go as reactants; balance equation; check states symbols |
Write the equation for the reaction of barium hydroxide with hydrochloric acid | Ba(OH)2 + 2 HCl BaCl2 + 2 H2O; check formulae!!!! |
Write the equation for the reaction of aluminium oxide with sulfuric acid | Al2O3 + 3 H2SO4 Al2(SO4)3 + 3 H2O; check formulae!!!! |
Write the equation for the reaction of Barium with water | Ba+ 2 H2O Ba(OH)2 + H2 |
Write the equation for the reaction of Magnesium with steam | Mg+ H2O MgO + H2 |
Use oxidation numbers to show that the reaction between Calcium and Water is a redox reaction | Ca+ 2H2O Ca(OH)2 + H2; Ca goes from 0 to +2=oxidation and H from +1 to 0=reduction; work out the oxidation state the elements that not combined first ; inside a compound H is ALWAYS +1 ie in H2O, H is NOT +2!!!! |
Describe and explain the trend of reactivity of group 2 metals down the group | As you go down the group, metals become more reactive; all have 2 e- in outer shell; as you go down, e- are further away from nucleus; more shielding; less attraction; less energy to remove e- ie to react SCARED |
Describe and explain the trend for the melting point of group 2 metals down the group | As you go down, mp decreases as the delocalised e- from the outer shell are further away from nucleus, so less attraction between delocalised e- and positive ions=weaker metallic bonds |
Describe and explain the trend of 1st IE of group 2 metals down the group | As you go down the group, atomic radius increases, e- are further away from nucleus; more shielding; less attraction; less energy to remove e- SCARED |
Describe the trend of solubilities of Group 2 hydroxides and group 2 sulfates as you go down teh group | As you go down the group, hydroxides become more soluble and sulphates less soluble (HBST=Hydroxide soluble at Bottom and Sulfates at Top) |
Explain whybarium hydroxide solution is more alkaline than Magnesium Hydroxide | Ba(OH)2 is more soluble than Mg(OH)2 so more Hydroxide ions OH- end up in solution hydroxide ions are alkaline |
Explain why patients eat a barium meal even when Barium ions are toxic | because the barium meal is barium sulfate; BaSO4 is insoluble so no Barium ION is dissolved, none will cross the intestine wall and go into blood stream |
Which group 2 metal does not fit the trend of decreasing melting point as you go down? | Magnesium |
During the test for sulfate ions, you add acidified Barium Chloride. Why should you NOT use sulphuric acid to acidify? | Otherwise the sulfate ions from H2SO4 would react with Barium ions and form a precipitate |
What is the least soluble Sulfate of group 2? | BaSO4 (HBST) |
Describe the explain the trend in boiling point (bp) of the Halogens as you go down the group | All Halogens are X2 formula and are simple covalent; all hav VdW forces BETWEEN MOLECULES; as you go down the group, the number of electrons increases so VdW forces BETWEEN MOLECULES will increase |
Describe the explain the trend in boiling point (bp) of the Hydrogen Halides HX as you go down the group | All HX are simple molecular; all has VdW and pd-pd; as you go down the group, elements are less electronegative so pd is weaker so pd-pd is weaker so bp will decrease (note VdW BTEWEEN MOLECULES increases) |
Write the IONIC equation for the reaction between Sodium Bromide and Chlorine | 2Br- + Cl2 Br2 + 2Cl-; SNAP ions do not show in an ionic equation; Check formulae; balance the equation; check states symbols |
Write the equation between Cl2 and cold water | Cl2 + H2O HCl + HClO; mnemotechnic ClOCl |
Write the equation between Cl2 and sodium hydroxide | Cl2 + NaOH NaCl + NaClO +H2O; mnemotechnic ClOCl; but you still need to remember H2O! |
Describe and write the IONIC equation for the test for chloride ions | add acidified silver nitrate; white precipitate forms; precipitate dissolves in dilute ammonia (did you remember the ammonia part of the test) Ag+ + Cl- AgCl |
Describe and write the IONIC equation for the test for bromide ions | add acidified silver nitrate; cream precipitate forms; precipitate dissolves in concentrated ammonia (did you remember the ammonia part of the test) Ag+ + Br- AgBr |
Describe and write the IONIC equation for the test for iodide ions | add acidified silver nitrate; yellow precipitate forms; precipitatedoes NOT dissolve in concentrated ammonia (did you remember the ammonia part of the test) Ag+ + I- AgI |
Explain why Nitric acid must be used to acidify the silver nitrate and not Sulfuric acid or hydrochloric acid? | otherwise precipitates of AgCl or Ag2SO4 form |
Why must Barium Chloride or Silver Nitrate be acidified before the tests for SO4-2 or Halide ions? | To remove carbonate ions |
Write the equation between solid sodium Chloride and concentrated sulphuric acid | NaCl + H2SO4 HCl + NaHSO4; mnemotechnic SHWI and SWOB |
Describe and explain your observations when solid sodium bromide is placed in concentrated H2SO4 | steamy fumes of HBr, and brown fumes of Br2; first NaBr + H2SO4 HBr + NaHSO4; then, the Br- ions reduce the conc H2SO4 (SWOB); note that SO2 is colourless |
Describe and explain your observations when solid sodium iodide is placed in concentrated H2SO4 | steamy fumes of HI, and black solid of I2 and rotten egg smell of H2S; first NaI + H2SO4 HI + NaHSO4; then, the I- ions reduce the conc H2SO4 (SHWI) ; note that SO2 is colourless |
Write the equation between Hydrogen Bromide and concentrated sulphuric acid | HBr+ H2SO4 SO2+ H2O+ Br2 ; mnemotechnic SHWI and SWOB |
Write the equation between Hydrogen Iodide and concentrated sulphuric acid | HI + H2SO4 H2S + H2O + I2; mnemotechnic SHWI and SWOB; then balance |
Explain why there is no reaction between Sodium Chloride and Bromine | Because Chlorine is a stronger oxidising agent than bromine and will not get displaced, REDUCED. KEYWORDS in Year 12: do not say “more reactive”=describe which is more oxidising; describe which gets REDUCED (ie not merely “displaced”) |
Describe and explain the trend of oxidising power of Halogens down the group | As you go down the group, outer shell is further away from the nucleus, any extra e- is less likely to be attracted so Iodine LESS likely to become Iodide and GET REDUCED; oxidising power decreases |
Describe and explain the trend of reducing power of Halide down the group | As you go down the group, outer shell is further away from the nucleus, e- less attracted to nucleus so Iodide MORE likely (than Chloride) to become IodiNe and GET OXIDISED; reducing power increases |