Notation 2, 8, 1 2, 8, 2 2, 8

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1 Page 90 Atomi struture 2 1 a Contains 3 protons (1); and 4 neutrons (1) Page 90 Eletroni struture 2 a 2, 8 Type of reation Ionisation Nulear fission Nulear fusion Change in mass of nuleus Stays the same Dereases Inreases (inreases/dereases/ stays the same) Change to the atom Loss or gain Nuleus splits; Two nulei join of eletrons into two together Periodi tale element Numer of eletrons Eletron arrangement Rememer: 3 a Calium aronate (1); alium magnesium aronate (1) Mention of exhange of ions (1); magnesium exhanges for alium (1) Chek whih grade you are working at Notation 2, 8, 1 2, 8, 2 2, 8 Page 91 Mass numer and isotopes 1 a (Similarity:) Both have 1 eletron in the outer shell (1) (Differene:) Different numers of eletrons / sodium has more eletrons / has an extra shell / has 8 more eletron (1) (Any 3:) Different atoms of hlorine have different masses; hlorine exists as isotopes; the relative atomi mass is an average value; takes into aount differenes in aundany as well as mass Page 91 Ioni onding 2 a Ca 2+ CaCl 2 3 a Ions are harged (1); ions an move (1) Pure water does not ondut eletriity (1); eause it does not ontain any ions (1) 1

2 Page 92 Ioni ompounds 1 a Ions are harged / have positive and negative harges (1); and are free to move (1) Ions in the solid annot move (1) 2 a Cross on the jewellery at the negative eletrode (1) Ions gain eletrons (1); one eletron is gained (1) Page 92 Covalent onding 3 a Doule (1) 4 shared eletrons (1) d Oxygen atoms have 6 eletrons in their outer shell (1); so need to gain two eletrons to form a stale arrangement (1) Atoms in the moleule are held together y strong onds (1); fores etween moleules (intermoleular fores) are very weak (1) Page 93 Simple moleules 1 a Water; it has a muh higher melting and oiling point; due to stronger fores etween the moleules (1) i Low oiling point so will evaporate too easily / perfume would not last in the ottle idea (1) ii Ethanol dissolves the fragrant oil and its oiling point is not far aove ody temperature (1) iii Boiling point too high so would not evaporate off the persons ody (1) Toxiity/ whether harmful to people / reativity / if it reaks down easily et. (1) Page 93 Giant ovalent strutures 2 a Graphite has weak onds etween layers (1); layers an reak off (1); all onds in diamond are very strong (1) There are spaes etween layers (1) Eletrons are free to move (1) 2

3 Page 94 Metals 1 a Eletrons an move (1) 2 a Atoms in the metal slide over eah other (1) i Conduts eletriity (1); onduts heat (1) ii Deloalised eletrons are free to move (1) Page 94 Alkali metals (2) 3 a Have only one or two eletrons in outer shell (1) Atom A (1); has one eletron in outer shell (1) Atom B (1); numers of protons are the same as numer of eletrons in an atom (1) Page 95 Halogens 1 a 1 (1) Sodium (1) 2 a i (1) Solution of Does it reat with Colour after ompound fluorine gas? reation Sodium hloride Yes Very pale green Sodium romide Yes Orange/rown Sodium iodide Yes Brown (2) ii Sodium fluoride; hlorine (1) Solution of ompound Sodium fluoride Sodium hloride Sodium iodide Does it reat with romine? No No Yes All 3 orret = (2) 2 or 1 orret = (1) Page 95 Nanopartiles 3 a Partiles ontaining a few hundred atoms (1); very small (1) They are in the form of hollow tues (1); with a very high surfae area (1) (Any 3:) Companies invest in new researh that might make profits in the future; nanopartiles have many uses that an e sold to make money; examples of uses of nanopartiles (example of uses of nanopartiles:) iosensors; harder wearing or stain resistant materials; information proessors; atalysts 3

4 Page 96 Smart materials 1 Spetales: A; ar dials: D; helmet: B; mugs C All orret = (4) 2 or 3 orret = (2) 1 orret = (1) Page 96 Compounds 2 a Elements ontain only one type of atom (1); ompounds ontain more than one type of atom hemially joined together (1) (Any 3:) In a mixture the elements are not hemially joined together; in a ompound the elements are hemially joined together; mixtures have different properties to the ompounds of the same elements; for example: hydrogen and oxygen are gases, water is a liquid The formula of water is H 2 O (1); whih shows that hydrogen and oxygen always reat in a 2:1 ratio (1) 3 a N H 2 2 NH 3 Mg + 2 HNO 3 Mg(NO 3 ) 2 + H 2 (4) Page 97 Perentage omposition 1 a Compound A is CO (1); ompound B is CO 2 (1) Compound B ontains a higher perentage than A (1) Page 97 Moles 2 a 32 g (1); 64 g (1) Mass of oxygen in SO 2 = 32 Perentage mass of sulfur in SO 2 = (64 32) x 100 (1) 640 tonnes (2) = 50 % (1) 4

5 Page 98 Perentage yield 1 a (Any 2:) Makes more produt; less reatants wasted; saves energy / fuel (Any 2:) Most of the atoms in the reatants are used up; to form produts; few atoms are left unreated Theoretial yield is the maximum alulated yield (1); atual yield is the amount otained in pratie (1) 2 a Mass of 1 mole magnesium = 24 g; mass of 1 mole magnesium oxide = 40 g (1) Mass of magnesium oxide made = 40 x 2.4 or 40 (1) = 4.0 g (1) perentage yield = atual yield theoretial yield perentage yield = 3 x 100 (1) 4 = 75% (1) Page 98 Reversile reations 3 a C 2 H 4 + H 2 O C 2 H 5 OH Corret layout and formulae = (1) reversile sign orret = (1) i H 2 O / CH 5 OH (1) ii C 2 H 4 (1) 5

6 Page 99 Equilirium 1 1 a A (1) (Any 2:) reation is reversile; do not get 100% yield; reyling gases means more will reat / etter yield Page 99 Haer proess 2 a i Inreases oth rate (1); and yield (1) Change to reation ondition A higher temperature A higher pressure Using less atalyst Effet on yield (inreases/ dereases/stays the same) Dereases Inreases Stays the same ii High pressures are expensive / diffiult to maintain / equipment needs to e speially designed / danger of leaks / not as safe to work with (1) (Any 2:) Reation is reversile; so do not get a high yield; reyles unreated hydrogen and nitrogen; inreases yield of ammonia (3) (3) 6

7 C2 B DISCOVER ELECTROLYSIS! C2 answers Page 101 Rates of reations 1 a i 90 = 1.8 (2) 50 ii Aid B (1); fastest reation (1) 1 temperature (1); 2 mass of magnesium (1); 3 volume of aid (1) Page 101 Following the rate of reation 2 a Time (1); volume of gas (1) No more gas will e made (1) Mass (1) (3) Rememer: Chek whih grade you are working at. Page 102 Collision theory 1 a i Aid partiles are loser together (not just more aid partiles) higher temperature (1) ii The partiles move faster (1) (Any 2:) Inreased surfae area of zin; higher frequeny of ollisions / more suessful ollisions (not just more ollisions); higher temperature / higher onentration / smaller lumps 2 a At a higher temperature, the onentration dereases (1); partiles move away from eah other and the gas expands (1) At a higher pressure, the onentration inreases (1); gas partiles are pushed together (1) Page 102 Heating things up 3 a Flask loses mass / gets lighter (1); eause reation produes aron dioxide (1); whih is a gas / leaves the flask / is lost (1) (Any 3:) Collisions are more frequent (1); more partiles have enough energy to reat (1); doule the numer of suessful ollisions our per seond (1) 7

8 C2 B DISCOVER ELECTROLYSIS! C2 answers Page 103 Grind it up, speed it up 1 a Large surfae area (1); most onentrated aid (1); highest temperature (1) i Any value less than 4.5 m 3 /s (1); aid is less onentrated (1); so reation is slower (1) ii Any value higher than 4.5 m 3 /s (with units) (1); higher temperature (1); inreases reation rate (1) Page 103 Conentrate now 2 a The aid (2) Aid is eing used up (1); onentration of aid falls (1); reations are slower at lower onentrations (1) Experiment 2 is less onentrated aid (1); so is at a slower rate (1) d i 5 m 3 (1) ii Beause this would exatly half the onentration of the aid (1); this will ause the rate to also halve (1) Page 104 Catalysts 1 a 2H 2 O + O 2 Formulae orret = (1) alaning orret = (1) (2) 0.2g / the same mass (1); eause a atalyst is not used up in the reation (1) 2 a It is not used up (1) (Any 2:) They have a very long lifetime / are not used up; they make reations faster; link to ost: more produts made quikly / do not need to uy more atalyst very often / works out heaper over time Page 104 Energy hanges 3 a Reation Temperature hange Exothermi or endothermi? Dissolving ammonium nitrate in water Dereases Endothermi Adding zin powder to opper Inreases Exothermi Adding magnesium rion to an aid Inreases Exothermi (2) Oxidation (1); neutralisation (1) 8

9 C2 B DISCOVER ELECTROLYSIS! C2 answers Page 105 Equilirium 2 1 a Caron monoxide (1) The forward reation is endothermi (1); therefore a low temperature will inrease the forward reation (1) Higher temperatures inrease the rate of reation (1) Page 105 Industrial proesses 2 a Nitrogen + hydrogen ammonia Corret names = (1) reversile sign orret = (1) i Iron ats as a atalyst (2) ii Inreases surfae area; speeds up rate of reation (2) i Nitrogen (1); hydrogen (1) ii Reation is reversile / reahes equilirium (1) 3 a Less than 15% (1) i A low temperature gives too low a reation rate (1); a high temperature gives too low a yield (1) ii A higher pressure gives a higher yield (1); and a faster rate of reation (1) iii Optimum onditions are a ompromise (1); etween yield and rate (1) Page 106 Free ions 1 a Contains harged ions (1); in a regular arrangement (1) Ions annot move in solid (1); ions move freely in solution (1) i Chlorine (1) ii (Any 2:) Positive eletrode / athode; eause it forms from hloride ions; whih are negatively harged Page 106 Eletrolysis equations 2 a Hydrogen (1) ii Sodium more reative than hydrogen / sodium very reative (1) To melt the sodium hloride (1); sodium hloride has a high melting point (1) i Na + + e (1) Na (1) ii Reation involves gain of eletrons (1) 9

10 C2 B DISCOVER ELECTROLYSIS! C2 answers Page 107 Uses for eltrolysis 1 a 2 a Copper (1); positive (1); gaining (1) Positive eletrode Cu(s) Cu 2+ (aq) + 2e Page 107 Aids and metals 3 a Add oth metals to samples of the aid (1); zin reats / fizzes eause it is more reative than hydrogen (1); opper does not reat eause it is less reative than hydrogen (1) Page 108 Making salts from ases 1 a Zin hloride (1) i Copper is too unreative to reat with an aid (1) ii Copper aronate (1) Negative eletrode Cu 2+ (aq) + 2e Cu(s) (6) Page 108 Aids and alkalis 2 a From lue to red (1) Beause it only has two olours / needs to e different olours at different phs (1) i Use the indiator to find out how muh aid he needs to add (1); repeat without indiator (1); using same amounts of aid and alkali (1) ii By evaporating the solution (1) 3 a All ontain nitrogen / all ontain ammonium ions (1) Ammonium nitrate (1) Sulfuri aid (1); H 2 SO 4 (1) d Compound C (1) 10

11 C2 B DISCOVER ELECTROLYSIS! C2 answers Page 109 Neutralisation 1 a i NaOH / Sodium hydroxide (1) ii Copper aronate (1) 2 a HCl(aq) H + (aq) + Cl (aq) Ions orret = (1) state symols orret = (1) i H + (aq) + OH (aq) H 2 O(l) (1) ii Solution Type of positive ion Type of negative ion NaOH Na + OH H 2 SO 4 H + SO 4 2 Na 2 SO 4 Na + SO 4 2 HBr H + Br All aids ontain H + (1); all alkalis ontain OH (1); neutralisation reation is the same every time (1) iii Lithium hloride (1) Page 109 Peripitation 3 a Lead aronate; lead hydroxide (1) Calium phosphate (1) (2) They are preipitates / solids (1); whih an e easily filtered off (1) 11