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26 t$="true ":
26 o$="true ":
14 t$="false":
14 o$="false":
12 e$="not correct":
8 t$="true "
8 o$="true "
8
5 e$="correct ":
4 s$="true "
4 s$="false"
4 r$="not correct"
4 r$="correct "
4 f$="true "
4 b$=" "
4 Second statement
4 Question ";n''"
4 Is the second statement true?
4 Is the 2nd statement a correct explanation of the 1st?
4 First Statement"
4 ;"Type y or n. "
4 ;"Type e for explanation/comment otherwise press the ENTER key."
4 ;"Type 1, 2 or 3."
4 ;"Press the ENTER key to continue."
4 ;"Is the first statement true?"
4 ;"1. A revision tutorial"''" 2. A simple test"''" 3. A copy of the questions"'" on your printer?";
4 ;" Educational Software "
4 ;"
4 ;"
4 )+("Well done."
4 )+("Very good."
4 )+("Good."
4 ("Excellent."
4 '"You correctly answered ";s;" out"'"of 10 questions."''
4 "correct "
4 "Your very low score indicates a poor understanding of this topic"
4 "You need to spend more time on this topic."
4 "You need to read through your notes and text-book again,"'"and then re-run this program."
4 "Well done."
4 "Well done, you were right.":
4 "No, You were wrong.":
4 "Good, you were right."''l$
4 "Do you want:";
4 "Do you want to run the program again?"
4 "Do you want to go through the questions in which you made"'"mistakes?"
4 "Both statements are true, and the 2nd is a correct explanationof the 1st."'l$'
4 " The second statement was ";t$;" ":
4 " The first statement was ";o$;" ":
4 is not the reason why
4 f$="false"
4 The fact that
4 Please type y
4 J J WARREN 1982
4 1982 J J Warren BSc ARCS Cert Ed "
3 "You were wrong. "''l$
3 S
2 "Your answer was wrong."
2 "You were wrong."
2 "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.":
2 "Well done, you were right."
1 physical change
1 overall charge +2
1 of the hydrogens of an acid arereplaced by metal ions."''"Potassium hydrogensulphate is"'"an
1 mass number
1 iron sulphide
1 into their constituent elements.":
1 in the series from solutions of their salts."''"
1 have different masses.":
1 greater than
1 gain electrons
1 fractional
1 delocalised
1 chemical change
1 chem4
1 chem3
1 chem2 T4
1 chem1
1 carbon dioxide
1 atomic number
1 as a consequence of
1 Zinc
1 Sodium
1 Silver
1 Reduction is the loss of oxygen
1 Reduction is the gain of"'"electrons.
1 Potassium
1 Oxidation is the gain of oxygen.
1 Oxidation is electron loss.
1 Melting points/degrees Celsius:
1 Magnesium
1 Lithium
1 Lead
1 Iron sulphide
1 Iron
1 H O (aq)+Cl (aq) 2 3"'''" +"'"H O is the hydrated hydrogen 3 ion. It is called the
1 For example:
1 For example
1 Copper
1 Calcium
1 An acid is a proton (hydrogen"'"ion) donor
1 Aluminium
1 Acid + Base
1 ;"Acids, Bases and Salts."
1 ;"2"''"Such substances usually dissolvewell in organic solvents."''"The iodine molecules are attrac-ted to the solvent molecules by van der Waals forces, and so theiodine dissolves.":
1 ;"- 2-"'" O + 4e
1 ;"- -"'" Cl + 2e
1 ;"+ -"'" Na
1 ;" Elements, Compounds, Mixtures and Separations."
1 ;" Redox, Electrolysis and the"'" Activity series."
1 ;" Structure, Bonding and Properties."
1 2,8,2 2,8 2
1 ."'''"The products of the reaction arecopper sulphate(blue) and water."'''"H SO + CuO
1 ."''"Therefore graphite
1 ."''"The solid which remains in the filter paper is called the"'"
1 ."''"No new substance is formed -"'"ice and water are forms of the same chemical compound."''"Melting is a change of physical state.":
1 ."''"New substances (zinc sulphate and hydrogen) are formed.":
1 ."''"For example, if the acid is"'"hydrochloric acid, then:"''"Na CO + 2HCl
1 . The partial ionic equation is:"''" 2- 2- + -"'"SO + H O
1 , when"'"potassium is burnt in oxygen, the oxygen gains electrons and is therefore reduced."'
1 , 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.":
1 )to ethane (CH
1 ) is classifiedas reduction":
1 ''''" Elements, Compounds, Mixtures and Separations."''"________________________________"''''
1 ''''" Redox, Electrolysis and the"'" Activity Series."''"________________________________"''''
1 ''''" Acids, Bases and Salts."''"________________________________"''''
1 ''''" Structure, Bonding and Properties."''"________________________________"''''
1 '"describes how the filter paper works, but does not explain why separation by filtration is"'"classified as a physical"'"separation technique.":
1 '" H O + SO
1 '" - -"'" 2Br
1 '" - -"'" I + 2e
1 "pH 7 corresponds to a neutral solution."''"Acids in aqueous solution give apH of
1 "Zinc metal will displace copper from copper sulphate solution":
1 "Zinc is the more reactive metal,and is oxidised to give"'"zinc (II) ions."''" 2+ -"'" Zn
1 "Zinc is below copper in the"'"activity series":
1 "With dilute hydrochloric acid:"''"
1 "When zinc reacts with iodine to form zinc iodide,"''"The zinc is
1 "When zinc reacts with iodine to form zinc iodide, the iodine is oxidised":
1 "When two electrodes are placed in water, and an electric"'"current is passed, hydrogen and oxygen are formed."''"A small amount of sulphuric acidis normally added to increase the electrical conductivity."''"Two volumes of hydrogen are"'"formed for every one volume of oxygen."
1 "When the two colourless"'"solutions are mixed, bright"'"yellow crystals of lead iodide are formed."''"Pb(NO ) + 2KI
1 "When molten lead bromide is"'"electrolysed, a brown vapour"'"comes off from the cathode":
1 "When copper sulphate solution iselectrolysed using graphite"'"electrodes, hydroxide ions are discharged at the anode":
1 "When copper (II) oxide is heatedin a stream of hydrogen, copper metal is formed":
1 "When ammonia gas is dissolved inwater it forms an alkaline"'"solution":
1 "Water passes through the filter paper, but particles of sand"'"do not":
1 "Water is a mixture of hydrogen and oxygen and not a compound":
1 "Water is a
1 "Water can be split up by"'"electrolysis to give hydrogen and oxygen":
1 "Unfortunately you were wrong."''l$
1 "Two different elements cannot have the same atomic number."''"The atomic number of neon is 10,and that of sodium is 11.":
1 "This is the modern definition ofreduction.
1 "This is the definition of a"'"compound."''"When elements are chemically"'"bonded together, they can only be separated by chemical"'"processes."''"Chemical reactions can break thebonds between atoms."'"Physical processes cannot do"'"this.":
1 "This is sometimes used as the"'"definition of an acid."''"
1 "This is a definition of the term""element""."''"""chemical means"" is stated so that radioactive decay and the atom-smashing methods of nuclearphysics are excluded.":
1 "This describes what happens"'"when the mixture of sand and"'"water is filtered."''"The liquid which passes through the filter paper is called the
1 "There is no simple relationship between colour and solubility, or between colour and extent of absorption."''"Therefore the colour of a"'"compound cannot
1 "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.":
1 "There are no common solid"'"
1 "The term ""substances"" in this"'"context refers to either "'"elements or compounds."''"The statement is effectively"'"the definition of a physical"'"change.":
1 "The solution of hydrogen"'"chloride in water is more fully"'"represented by:"'''," + -"'"HCl(g)+H O(l)
1 "The sodium ion and the neon atomhave the same electron"'"configurations":
1 "The sodium ion and the neon atomhave the same atomic number":
1 "The separation of sand from"'"water by filtration is a"'"physical method of separation":
1 "The reaction is started by"'"heating the magnesium strongly in a bunsen flame."''"The magnesium oxide formed has quite different properties to either the magnesium metal or the oxygen."''"A new compound is formed.":
1 "The properties of iron sulphide are different from those of ironand sulphur":
1 "The overall equation for the"'"reaction is:"''" Zn + I
1 "The only solid elements which"'"conduct electricity are metals":
1 "The nitrogen atom has only threeelectrons in the outer shell":
1 "The nitrogen atom can form threecovalent bonds":
1 "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.":
1 "The melting of ice to form wateris an example of a chemical"'"change":
1 "The melting of ice to form wateris a
1 "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.":
1 "The magnesium atom has 12"'"protons in the nucleus, and 12 extra-nuclear electrons."''"Its electron configuration is 2,8,2"''"The two outer shell electrons are easily given up."''"This results in the formation of an ion with two positive"'"charges."
1 "The magnesium atom forms an ion with two positive charges":
1 "The magnesium atom forms an ion with two positive charges"'"
1 "The iodine atom has one less"'"outer shell electron than the"'"following rare gas":
1 "The hydrogen ions (protons) are bonded to water molecules"'"forming
1 "The distance moved by a"'"substance on chromatography"'"paper is determined by its"'"colour":
1 "The distance moved by a compoundon chromatography paper is"'"determined by:"''"
1 "The covalent bonds between the atoms of non-metals are rather weak":
1 "The conversion of sulphite ions to sulphate ions is neither"'"oxidation nor reduction":
1 "The conversion of sulphite ions to sulphate ions is
1 "The colourless gas is carbon dioxide."''"
1 "The colourless gas formed when acids react with sodium"'"carbonate is
1 "The coloured substances found ingrass can be separated by paper chromatography":
1 "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":
1 "The chromatogram is developed byallowing a solvent to rise up the paper by capillary action."''"A number of green and yellow"'"spots rise to different"'"positions. Each spot is a"'"different coloured compound.":
1 "The chlorine atom easily loses one electron to give a rare gas electron configuration":
1 "The chloride ion has a single negative charge.":
1 "The charge on the sulphite ion is the same as the charge on thesulphate ion":
1 "The change which occurs when"'"magnesium is burned in air is classified as a chemical change":
1 "The change from molecular iodineto iodide ions involves the gainof electrons":
1 "The change from ethene (CH
1 "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
1 "The anions present are hydroxideions (from the ionisation of"'"water) and sulphate ions."'"The hydroxide ions are"'"discharged to give oxygen gas:"''" - -"'"4OH
1 "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.":
1 "The Halogens (fluorine,"'"chlorine, bromine and iodine) all form ions with a single"'"negative charge."'''" - - - -"'" F Cl Br I":
1 "Sulphur dioxide is an acidic"'"oxide."''"It dissolves in water to give sulphurous acid."'''"
1 "Sulphur dioxide dissolves in"'"water to form sulphurous acid":
1 "Solid sodium chloride consists of sodium ions and chloride ionsheld together by electrostatic attraction."''"The regular arrangement of ions is called an ionic crystal"'"lattice.":
1 "Solid sodium chloride conducts electricity":
1 "Sodium configuration: 2,8,1"''"Neon configuration: 2,8"''"Sodium easily loses its one"'"outer shell electron to give a configuration of 2,8 - the same as that of neon."''
1 "Sodium chloride is an ionic"'"solid at room temperature and pressure":
1 "Silver-grey magnesium metal"'"burns with a brilliant white"'"flame to form a white powder."''"A considerable amount of heat is given out, and the change"'"cannot be easily reversed.":
1 "Silver metal reacts with dilute hydrochloric acid to liberate hydrogen gas":
1 "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.":
1 "Silver is above hydrogen in the activity (electrochemical)"'"series":
1 "Sand and water together form a mixture."''"No new chemical substances are formed when this mixture is"'"separated. The water and the"'"sand were present both before and after the filtration."''"A change which does not involve the creation of new chemical"'"substances is classified as a physical change.":
1 "Reduction is the process by"'"which atoms, molecules or ions gain electrons":
1 "Reduction can be defined as a process involving the addition of hydrogen to a substance":
1 "Potassium hydrogensulphate is a normal salt":
1 "Potassium hydrogensulphate is formed when equal numbers of"'"moles of potassium hydroxide andsulphuric acid are mixed":
1 "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
1 "Physical separation techniques include:"''" filtration"'" distillation"'" chromatography"''"These methods can only be"'"used to separate
1 "Oxygen is a gas at room"'"temperature and pressure":
1 "Oxygen consists of small,"'"diatomic molecules:"''," O"'," 2"''"The forces of attraction betweenthese molecules are very weak."''"As a result, oxygen is a gas at room temperature and pressure.":
1 "Oxygen can form both ionic and covalent bonds":
1 "Oxygen (2,6) can get a rare gas electron configuration by:"'''"(1) Gaining two electrons to"'"form the oxide ion as in"'"magnesium oxide."''"(2) Forming two covalent bonds as in water.":
1 "Oxidation is the process by"'"which atoms, molecules or ions
1 "Other definitions include:"''"
1 "Non-metals which exist as small molecules do have low melting points (e.g. nitrogen and"'"chlorine)."''"However, non-metals with giant covalent lattice structures havevery high melting points"'"(e.g. carbon and silicon)."''"
1 "Nitrogen is in Group 5B of the Periodic Table, It has
1 "Nitrogen has the electron"'"configuration 2,5."''"If it gains a share in three"'"more electrons, it will have a configuration like that of neon (2,8)."'"It can do this by forming three covalent bonds, as in the"'"ammonia molecule:"'
1 "Most carbon atoms have 6 protonsand 6 neutrons in the nucleus (6+6 gives a
1 "Metals high in the activity"'"series have good reducing"'"properties":
1 "Metal sulphates always give"'"colourless aqueous solutions":
1 "Many acids are formed when non- metal oxides are dissolved in water."'"E.g., sulphur trioxide dissolves to give sulphuric acid:"''" H O + SO
1 "Magnesium reacts with oxygen"'"from the air to form a new"'"compound":
1 "Magnesium is in Group 2A of the periodic table":
1 "Magnesium is in Group 2A of the Periodic Table because it has similar physical and chemical properties to the other elementsin the group."''"The Group 2A elements are:"''"
1 "Liquid oxygen boils at -183 and liquid nitrogen at -196 degrees Celsius."''"The small difference in boiling points allows the two liquids tobe separated by fractional"'"distillation."''"The liquid nitrogen has the"'"lower boiling point, and so"'"distils off first.":
1 "Liquid oxygen and liquid"'"nitrogen have different boiling points":
1 "Liquid air is separated into"'"oxygen and nitrogen by"'"
1 "Liquefied air can be separated into oxygen and nitrogen by"'"simple distillation":
1 "Lime-water is a saturated"'"solution of calcium hydroxide."''"This reacts with carbon dioxide to give calcium carbonate."''"Ca(OH) + CO
1 "Lead iodide is quite soluble in hot water":
1 "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.":
1 "Lead iodide can be prepared by mixing cold solutions of lead nitrate and potassium iodide":
1 "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.":
1 "Iron and sulphur combine in"'"fixed proportions by mass to"'"form iron sulphide":
1 "Iodine is an element in Group 7Bof the Periodic Table."''"It has seven outer shell"'"electrons - one less than the rare gas xenon, which has eight.":
1 "Iodine exists as small covalent molecules (I )."'
1 "Iodine dissolves well in organicsolvents":
1 "In graphite the carbon atoms arecovalently bonded together in sheets."''"Each carbon atom uses three"'"electrons to form normal"'"covalent bonds to its neighbours"''"The forth outer shell electron of each carbon atom is free to move and carry an electric"'"current - it is
1 "Hydroxide ions have a single"'"negative charge, whereas"'"sulphate ions have a double"'"negative charge":
1 "Hydrogen chloride is very"'"soluble in water."''"When it dissolves the molecules split up to form ions. The ions are hydrated.":
1 "Hydrochloric acid is formed by dissolving hydrogen chloride gasin water":
1 "Hydrochloric acid is a strong acid":
1 "However, zinc dissolving in"'"hydrochloric acid is a
1 "Heat energy must be provided to melt ice":
1 "H SO + KOH
1 "Grass is ground up with a"'"liquid to extract the pigments (coloured substances)."''"A spot of the solution obtained is placed near the bottom of thechromatography paper."
1 "Graphite is a non-conductor of electricity":
1 "Good, your answer was right."
1 "Good, your answer was correct."
1 "Ethanoic acid dissolves in waterto give a solution of pH 7":
1 "Ethanoic (acetic) acid in"'"aqueous solution is a weak acid":
1 "Elemental chlorine oxidises"'"iron (II) ions":
1 "Each element has its own atomic number."''"All carbon atoms have 6 protons in the nucleus and 6 electrons outside it."''"Therefore all carbon atoms"'"have an atomic number of 6.":
1 "During electrolysis reduction takes place at the cathode":
1 "CuO + H
1 "Covalent bonds are
1 "Copper (II) oxide is a reducing agent":
1 "Chlorine molecules can take"'"electrons from iron (II) ions":
1 "Chlorine (2,8,7)
1 "Changes such as water boiling"'"and salt dissolving in water"'"are physical changes":
1 "Carbon dioxide turns lime-water milky":
1 "Carbon dioxide is classified as an acidic oxide":
1 "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." :
1 "Carbon dioxide dissolves in"'"water giving carbonic acid:"''" H O + CO
1 "Bromine is formed at the
1 "Both ions have a double negativecharge:"'''" 2-"," 2-"'" SO","SO"'" 3"," 4"''"sulphite sulphate":
1 "Boiling is a change of physical state - no new chemical"'"substance is formed."''"When substances like salt or"'"sugar dissolve in water, no new compound is formed. The salt or sugar particles just mix in withthe water."
1 "Black copper oxide does dissolvein dilute sulphuric acid, but"'"the solution formed is
1 "Black copper oxide dissolves in dilute sulphuric acid to form a colourless solution":
1 "Attractive forces exist between the water molecules in ice."'"These forces hold the molecules in an orderly crystal structure."''"Heat energy can overcome these attractive forces. Then the "'"molecules can move around freelyas liquid water."''"The molecules are not broken, just separated. No new chemical substance is formed.":
1 "Atoms of different isotopes of an element have different"'"masses."''"Although all carbon atoms have 6 protons, they can have"'"different numbers of neutrons.":
1 "An element is made of"'"indivisible and indestructible particles called molecules":
1 "An element is a substance which cannot be split into simpler"'"substances by chemical means":
1 "Ammonia reacts with water to"'"form hydroxide ions":
1 "Ammonia is a
1 "Ammonia acts as a base by"'"accepting a hydrogen ion from a water molecule."''"This yields ammonium and"'"hydroxide ions:"''," + -"'"NH + H O
1 "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.":
1 "Although some elements normally exist as molecules, the majoritydo not."''"Molecules can be broken up to give atoms, so they are not"'"indivisible."''"The atomic theory suggests that:"''"
1 "Although both statements are"'"true, there is no simple"'"connection between them."'''"Iodine dissolves well in organicsolvents"'"
1 "All pure samples of the same"'"chemical compound contain the same elements combined in fixed proportions by mass."''"This is because elements consistof atoms which combine together in a fixed ratio when compounds are formed.":
1 "All non-metals have low melting points.":
1 "All metallic elements contain mobile electrons which act as charge carriers."''"Graphite is a form of the
1 "All atoms of carbon have the"'"same mass":
1 "All atoms of carbon have the"'"same atomic number":
1 "All acids may be formed by"'"dissolving non-metal oxides in water":
1 "All acids contain oxygen":
1 "Addition of hydrogen has taken place, therefore the change is reduction."''"CH =CH + H
1 "Acids react with sodium"'"carbonate giving a colourless"'"gas":
1 "Acids contain hydrogen which maybe replaced by a metal":
1 "A weak acid is one which is only
1 "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
1 "A solution of sulphur dioxide in water turns red litmus blue":
1 "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
1 "A compound consists of two or more elements chemically bonded together":
1 "A compound cannot be separated into simpler substances by"'"physical separation techniques":
1 "A compound and its constituent elements are different chemical substances."''"Different chemical substances"'"have diffent chemical"'"properties.":
1 "A change is described as a"'"physical change if no new"'"substances are formed":
1 "''''"The magnesium ion still has"'"12 protons in the nucleus, but it only has 10 electrons."''''" charge on protons +12"'" charge on electrons -10"''"
1 "''"its atoms can attain more stableelectron configurations by"'"either gaining or sharing"'"electrons.":
1 "''"This reaction is characteristic of acids.":
1 "''"These electrons are taken from iron (II) ions."''"The chlorine molecules are"'"reduced to chloride ions.":
1 "''" 2+ 2+"'"Zn(s)+ Cu (aq)
1 "''"
1 "'"the inter-molecular attractions between the iodine molecules andthe solvent molecules can over- come the weak forces which hold the iodine molecules together inthe iodine crystal.":
1 "'"no new chemical substances are formed."''"The statement that"':
1 "'"nitrogen -210"'"chlorine -101"'"carbon 3727 (sublimes)"'"silicon 1410":
1 "'"its atomic structure and"'"electron configuration."'''"The Periodic Table is simply a list of the elements arranged in a special way."''"A list cannot
1 " -"," 2-"'" OH","SO"'," 4"''"Hydroxide Sulphate"' " ion ion":
1 " 2+ -"'" Mg
1 why an"'"ion has two positive charges.":
1 which conduct"'"electricity."''"This is because solid compounds do not contain
1 to water."''"The copper (II) oxide has acted as an
1 to iodideions.":
1 to copper metal, and the hydrogen is
1 themolecules, chlorine is a gas at room temperature and pressure.":
1 the distance that it travels on the chromatography paper.":
1 shows neither of these properties.":
1 salt."'''" H SO KHSO K SO"'" 2 4 4 2 4"''"
1 salt is formed when
1 reactivity.
1 oxygen forms both ionic and covalent bonds."'''"Oxygen forms both ionic and"'"covalent bonds"''"
1 outer shell electrons."'''"Nitrogen configuration: 2,5":
1 order of decreasing
1 one"'"electron giving a configuration like that of argon(2,8,8)."'''" - -"'" Cl + e
1 of"'"substances."''"They cannot break down
1 of hydrogen and oxygen."''"Water can be formed by burning hydrogen in oxygen - a chemical change. A lot of energy is"'"released, and a new substance isformed."''"2H + O
1 of 12).These are atoms of the isotope carbon-12."''"Some carbon atoms contain"'"6 protons and
1 neutrons"'"(6+8 gives a mass number of 14).These are atoms of the isotope carbon-14."''"This means that carbon atoms
1 lists the metals in
1 its solubility in the solvent;
1 is magnetic;"'"
1 is equal to"'"the number of protons in the"'"nucleus of the atom."''"It is also equal to the number of electrons around the nucleus of the neutral atom.":
1 ions:"''''"
1 ionised."''"In water, most of the ethanoic acid is present as molecules."'"Only a small proportion is"'"ionised."''," - +"'" CH CO H
1 in the activity"'"series can displace metals
1 hydrogen in the
1 hydrogen from acids.
1 how strongly it is absorbed by the paper."''"Very soluble, weakly absorbed substances move furthest."''"Insoluble, strongly absorbed"'"substances do not move at all."
1 has no reaction."'''"
1 gives odourless hydrogen;
1 gives hydrogen"'"sulphide gas (rotten egg smell);
1 gives "''"Salt + Carbon Dioxide + Water
1 from the zinc"'"atoms, and are
1 electrons."''"When an iron (II) ion loses one electron, an iron (III) ion is formed."''" 2+ 3+ -"'" Fe
1 distillation."''"Simple distillation is used to separate a liquid from non-"'"volatile solids."''"To separate liquids with similarboiling points, the repeated"'"condensation and re-evaporation which occurs in a fractionating column is necessary.":
1 dissolves in some"'"organic solvents;"'"
1 copper in the"'"activity series."''"
1 charge"'"carriers."''"However, sodium chloride does conduct electricity when melted or dissolved in water."''"This is because its ions are"'"then free to move and carry"'"charge.":
1 bonds."''"The chlorine molecule consists of two atoms strongly held"'"together by a covalent bond."''"However, as there are only weak van der Waals forces
1 atoms cannot be created or"'" destroyed (by chemical means);
1 are both below
1 and so gives asolution with a pH
1 all matter is made of atoms;
1 all atoms of a given element are (chemically) identical.":
1 agent in this reaction":
1 activity series.
1 a"'"conductor of electricity.":
1 a gas at rtp,but this cannot explain
1 Zn (aq)+ Cu(s)":
1 The activity series
1 Sr strontium
1 Ra radium
1 Potassium "'" Sodium "'" Lithium "'" Calcium "'" Magnesium "'" Aluminium "'"
1 Neither can liberate
1 Mg magnesium
1 Copper and silver
1 CaCO + H O 2 2 3 2"''"The calcium carbonate formed is insoluble in water, and forms a milky-white suspension.":
1 Ca calcium
1 CH CH"'" 2 2 2 3 3"''"The reaction takes place when ethene gas and hydrogen are"'"passed over a heated nickel"'"catalyst.":
1 Be beryllium
1 Ba barium
1 Acids turn blue litmus red.
1 Acid + Metal Carbonate
1 7."''''"The pH of dilute ethanoic acid solution is about 3."''"(The exact value depends upon the concentration).":
1 7."''"Ammonia solution turns red"'"litmus blue, thus showing that the solution is alkaline.":
1 2NaCl + CO + H O
1 + 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.":
1 (loses"'"electrons)"'" 2+ -"'" Zn
1 (gains"'"electrons)"'" - -"'" I + 2e
1 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."
1 metal carbon."''"Although graphite has a giant covalent lattice structure, it does have mobile electrons. It is a fairly good conductor of electricity."''"So at least one non-metallic"'"element conducts electricity.":
1 ZnI"'" 2 2"''"Zinc iodide is an ionic"'"compound.":
1 Zn + 2e"''"The iodine is
1 Zn + 2e"''"The electrons from the zinc"'"reduce the copper (II) ions to copper metal."''" 2+ -"'" Cu + 2e
1 Salt + Water
1 SO +2H + 2e"'" 3 2 4"''"The sulphite ions give up"'"electrons and gain oxygen."''"
1 PbI + 2KNO 3 2 2 3"''"The precipitated lead iodide canbe separated from the potassium nitrate solution by filtration.":
1 O + 2H O + 4e"'" 2 2"''"Some carbon dioxide is formed due to oxidation of the graphiteanode by the oxygen.":
1 Na CO + H O 2 2 3 2":
1 Na + e"''" 2,8,1 2,8 1":
1 NH + OH 3 2 4"''"The hydroxide ions make the"'"solution alkaline.":
1 Mg + 2e"'"
1 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.":
1 K + e":
1 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.":
1 H SO"'" 2 2 2 3"''"The sulphurous acid ionises to give hydrogen and sulphite ions:"'',"+ 2-"'" H SO
1 H CO "'" 2 2 2 3"''"Carbon dioxide also reacts with and neutralises bases, for"'"example, with sodium hydroxide solution:"''" CO + 2NaOH
1 CuSO + H O 2 4 4 2"''"
1 Cu + H O"'" 2 2"''"Copper (II) oxide is
1 Cu + H O"'" 2 2":
1 Br + 2e"'" 2":
1 4K + 4e":
1 2O"'" 2"''"The electrons come from the"'"potassium, which is oxidised."'" + -"'" 4K
1 2I"'" 2"''"In the reaction between iodine and zinc, the iodine molecules
1 2I"'" 2"
1 2H + SO"'" 2 3 3"''"The hydrogen ions make the"'"solution acidic.":
1 2Cl"'" 2"'"
1 2 3 2 2":
1 H + Cl"
1 Fe + e"''"The electrons are taken by the chlorine, which acts as an"'"oxidising agent.":
1 Cl"''"2,8,7 1 2,8,8":
1 CH CO + H"'" 3 2 3 2":
1 2H O 2 2 2"''"The proportions of hydrogen and oxygen combined together are in a fixed ratio.":
1 "'" Silver
1 "'" Iron "'" Lead "'"
1
1
1