1、 Boardworks Ltd 20041 of 20 Boardworks Ltd 20051 of 36KS3 Chemistry8F Compounds and Mixtures Boardworks Ltd 20041 of 20 Boardworks Ltd 20052 of 368F Compounds and Mixtures Mixtures Summary activities Comparing elements and compounds Compound names and formulae Contents Word equations Boardworks Ltd
2、20041 of 20 Boardworks Ltd 20053 of 36 Properties of elements and compoundsWhy is it safe to put sodium chloride on fish and chips but not safe to use sodium and chlorine?Boardworks Ltd 20041 of 20 Boardworks Ltd 20054 of 36Compounds contain two or more different types of atom.Elements are materials
3、 made up of one type of atom only.Atoms in elements and compoundsThe element,hydrogen,exists as molecules.Each hydrogen molecule is made up of two hydrogen atoms joined together.The compound,water,exists as molecules.Each water molecule consists of two hydrogen atoms joined to one oxygen atom.H H Bo
4、ardworks Ltd 20041 of 20 Boardworks Ltd 20055 of 36 Element or compound?Boardworks Ltd 20041 of 20 Boardworks Ltd 20056 of 36A compound is made when atoms of different elements react and join together.For example,water is produced from the chemical reaction between hydrogen and oxygen.Making a compo
5、und waterTwo hydrogen molecules react with one oxygen molecule to produce two molecules of water.+H HH HOOhydrogenoxygenwater+Why does water have different properties to its elements?Boardworks Ltd 20041 of 20 Boardworks Ltd 20057 of 36 Properties of a compound carbon dioxideA compound has different
6、 properties to the elements from which it is made because the atoms are joined differently.Black solid used as fuel.Colourless gas in which many substances burn.Colourless gas used in fizzy drinks and fire extinguishers.+O OCcarbonoxygencarbon dioxide+Boardworks Ltd 20041 of 20 Boardworks Ltd 20058
7、of 36 A compound is not a mixtureThe atoms in water,the compound made when hydrogen and oxygen react and their atoms become chemically joined to each other,look like thisThe atoms in a mixture of hydrogen gas and oxygen gas,which have not reacted with each other,look like this Boardworks Ltd 20041 o
8、f 20 Boardworks Ltd 20059 of 368F Compounds and Mixtures Mixtures Summary activities Comparing elements and compounds Contents Word equations Compound names and formulae Boardworks Ltd 20041 of 20 Boardworks Ltd 200510 of 36To name simple compounds of metals and non-metals:Naming simple compounds2.W
9、rite down the name of the non-metal,changing the ending of the word to “-ide”.1.Write down the name of the metal.What is the name of the compound made when the following elements combine?l magnesium and oxygenl sodium and chlorinel oxygen and ironmagnesium oxidesodium chlorideiron oxide Boardworks L
10、td 20041 of 20 Boardworks Ltd 200511 of 36What is the name of each compound formed by these metal and non-metal elements?nitrogenlithiumsulphurzinciodinenickelbrominealuminiumoxygentinchlorinesodiumnitrogenmagnesiumsulphuriron Name of compoundElement 2Element 1iron sulphidemagnesium nitridesodium ch
11、loridetin oxidealuminium bromidenickel iodidezinc sulphidelithium nitride Naming simple compounds Boardworks Ltd 20041 of 20 Boardworks Ltd 200512 of 36Many compounds contain more than two elements.oxygenbrominealuminiumoxygensulphurcopperoxygenoxygenoxygenElement 3nitrogensodiummagnesium nitratenit
12、rogenmagnesium nickel sulphatesulphurnickelName of compoundElement 2Element 1sodium nitratecopper sulphatealuminium bromate Naming further compoundsFor compounds containing two elements plus oxygen,the ending of the other non-metal usually changes to“ate”.Boardworks Ltd 20041 of 20 Boardworks Ltd 20
13、0513 of 36A compound always contains a particular amount of each element.It has a fixed composition.Composition of compoundsA compound contains atoms from different elements that are chemically joined together.Compound names can get quite long and complicated,so the symbols of the elements are used
14、as a shorthand.The symbols of the elements in a compound are combined to give the formula of the compound.What is the formula of carbon dioxide?Boardworks Ltd 20041 of 20 Boardworks Ltd 200514 of 36carbon dioxideA formula uses the symbols of the elements in a compound.When there is more than one ato
15、m of each element,the number is always written after the symbol.Writing a formulacarbon atom =1formula=hydrogen atoms=2formula=The formula shows the ratio of atoms in a compound.waterCO2H2Ooxygen atoms=2oxygen atom =1 Boardworks Ltd 20041 of 20 Boardworks Ltd 200515 of 361.Titanium oxideFor every ti
16、tanium atom there are two oxygen atoms.Formula=2.Lithium oxide For every two lithium atoms there is one oxygen atom.Formula=3.Aluminium chloride For every aluminium atom there are three chlorine atoms.Formula=What is the formula of each of these compounds?What is the formula?TiO2Li2OAlCl3(In a formu
17、la put the metal first as when naming a compound.)Boardworks Ltd 20041 of 20 Boardworks Ltd 200516 of 361.Silicon chlorideFor every silicon atom there are four chlorine atoms.Formula=2.Manganese oxide For every manganese atom there are two oxygen atoms.Formula=3.Aluminium oxide For every two alumini
18、um atoms there are three oxygen atoms.Formula=What is the formula of each of these compounds?What is the formula?SiCl4MnO2Al2O3(In a formula put the metal first as when naming a compound.)Boardworks Ltd 20041 of 20 Boardworks Ltd 200517 of 36 What is the ratio of atoms?Boardworks Ltd 20041 of 20 Boa
19、rdworks Ltd 200518 of 36 What does a formula show?Boardworks Ltd 20041 of 20 Boardworks Ltd 200519 of 368F Compounds and Mixtures Mixtures Summary activities Comparing elements and compounds Contents Word equations Compound names and formulae Boardworks Ltd 20041 of 20 Boardworks Ltd 200520 of 36 Wr
20、iting a word equationA word equation can be used to describe any chemical reaction,i.e.any process in which atoms become joined in different ways.The steps for writing a word equation are:On the right-handside,put the name of the reactant(s).If there are two or more reactants,link them with a sign.2
21、.In the middle,write down an arrow().3.On the right-handside,put the name of the product(s).If there are two or more products,link them with a sign.Boardworks Ltd 20041 of 20 Boardworks Ltd 200521 of 36The lead and oxygen dont mix,they react to form lead oxide.This means that the lead and oxygen ato
22、ms in the product are joined differently to the atoms in the reactants.Lead reacts with oxygen to form lead oxide.lead +oxygen lead oxideWhy is lead oxide so different to both lead and oxygen?What is the word equation?What is the word equation for this reaction?Boardworks Ltd 20041 of 20 Boardworks
23、Ltd 200522 of 36Limestone(calcium carbonate)is heated to make calcium oxide and carbon dioxide.Magnesium reacts with hydrochloric acid to make magnesium chloride and hydrogen.Methane is burnt to make carbon dioxide and water.calcium carbonate calcium oxide+carbon dioxidemagnesium+hydrochloric acid m
24、agnesium chloride+hydrogen methane+oxygen carbon dioxide+water What is the word equation?Write out word equations for the following chemical reactions.Boardworks Ltd 20041 of 20 Boardworks Ltd 200523 of 368F Compounds and Mixtures Mixtures Summary activities Comparing elements and compounds Contents
25、 Word equations Compound names and formulae Boardworks Ltd 20041 of 20 Boardworks Ltd 200524 of 36A mixture is not the same as a compound:The proportions of the substances in a mixture are not fixed.The properties of a mixture are often an“average”of the properties of its ingredients(e.g.a mixture o
26、f a black and white powder is grey).3.The substances in a mixture are just mixed,not chemically joined,and so it is usually quite easy to separate the A mixture contains two or more substances that are together but have not reacted with each other.Sea water is a mixture of salts,water and other subs
27、tances.What is a mixture?ingredients(e.g.it is easy to get salt from sea water).Boardworks Ltd 20041 of 20 Boardworks Ltd 200525 of 36 Element,compound or mixture?Boardworks Ltd 20041 of 20 Boardworks Ltd 200526 of 36 Element,compound or mixture?Boardworks Ltd 20041 of 20 Boardworks Ltd 200527 of 36
28、Liquids that do not mix are described as immiscible.Examples of immiscible liquids are water with oil and water with petrol.On a small scale,immiscible liquids can be separated by simply removing the top layer using a pipette.oilwaterwateroil Separating immiscible liquids Boardworks Ltd 20041 of 20
29、Boardworks Ltd 200528 of 36Liquids that do mix are described as miscible.Examples of miscible liquids are water with alcohol and petrol with kerosine.Miscible liquids can be separated by heating them to boiling.The components of the mixture have different boiling points and so will boil off at diffe
30、rent temperatures.A condenser is used to recover the liquids as they boil off.This piece of apparatus is a tube that has cold water circulating around the outside.It cools down vapours and condenses them back to a liquid.Substances with low boiling points are collected first,while those with higher
31、boiling points are collected later.Separating miscible liquids Boardworks Ltd 20041 of 20 Boardworks Ltd 200529 of 36 Distillation apparatus Boardworks Ltd 20041 of 20 Boardworks Ltd 200530 of 36How can each mixture be separated?alcoholalcohol and watercooking oilcooking oil and waterwatersea waters
32、altsea waterglassglass and waterMethodWantedMixturefilterevaporatedistilpipettedistil Separating mixtures Boardworks Ltd 20041 of 20 Boardworks Ltd 200531 of 36Reggie has been given a mixture of salt,sand and water.He needs to separate these three substances but cannot remember how,so Reggie needs y
33、our help!Experiment to separate a mixtureWrite an experimental plan for Reggie to follow so that he will end up with the sand,salt and water in separate containers.Start your plan with a list of the equipment that is needed for separating this mixture.Then write a step by step plan that is easy for
34、Reggie or anyone else to follow.Boardworks Ltd 20041 of 20 Boardworks Ltd 200532 of 368F Compounds and Mixtures Mixtures Summary activities Comparing elements and compounds Contents Word equations Compound names and formulae Boardworks Ltd 20041 of 20 Boardworks Ltd 200533 of 36 Glossaryatom The sma
35、llest particle that can exist on its own.boiling point Temperature at which a pure liquid becomes a pound Substance made up of two or more different types of atoms that are chemically joined together.element Substance made up of only one type of atom.formula The symbols and numbers that represent th
36、e ratio of different atoms in a substance.immiscible Liquids which do not mix.miscible Liquids which do mix.mixture Two or more substances that are mixed but not chemically joined together.Boardworks Ltd 20041 of 20 Boardworks Ltd 200534 of 36 Anagrams Boardworks Ltd 20041 of 20 Boardworks Ltd 200535 of 36 True or false?Boardworks Ltd 20041 of 20 Boardworks Ltd 200536 of 36 Multiple-choice quiz
