F4 Chemistry Chapter 3 : Chemical Formulae and EquationsCHAPTER 3 : CHEMICAL FORMULAE AND EQUATIONSA RELATIVE ATOMIC MASS (RAM)AND RELATIVE MOLECULAR MASS (RMM)Learning Out!"e#You should be able to: state the meaning of relative atomic mass based on carbon-12 scale, state the meaning of relative molecular mass based on carbon-12 scale, state why carbon-12 is used as a standard for determining relative atomic mass and relative molecular mass, calculate the relative molecular mass of substances.Ati$it% & (refer text book pg 28 )Re'ati$e at!"i "a## !( an e'e"ent ) Ar = The average mass of an atom of the element 1/12 x the mass of an atom of carbon-12Example: Ar of =12Ar of !=1"Ar of #g=2$1. The %elat&ve atom&c mass of an element &s '''''''''''''''''''''''((('''''''''''''()hen compare )&th 1/12 of the mass of an atom of carbon * 12(2(arbon-12 &s chosen beca+se &t &s a '''''''''(an, can be eas&l- han,le,(.( /&n, the relat&ve atom&c massesof these elements(Element %elat&ve Atom&c #ass Element %elat&ve Atom&c #assalc&+m0 a Argon0 Ar1o,&+m0 2a 1&lver0 Ag3ron0 /e aes&+m0 sopper0 + 4ea,0 5barbon0hlor&ne0 l6-,rogen0 6 /lo+r&ne0 /5otass&+m0 7 Al+m&n&+m0 Al4&th&+m0 4& 8&nc0 8n9rom&ne0 9r 6el&+m0 6eAti$it% * (refer text book pg 2: )Re'ati$e "!'eu'ar "a## !( a #u+#tane) Mr= The Average mass of a molec+le of the s+bstance1/12 x the mass of an atom of carbon-121 F4 Chemistry Chapter 3 : Chemical Formulae and EquationsCalculating Relative molecular mass,Mr#r= The s+m of Ar of all atoms present &n one molec+leExample:#r of ;ater0 62! = 2(1) < 1" = 18#r of arbon ,&ox&,e0 !2 = 12 < 2(1") = $$/or &on&c s+bstance 0 Re'ati$e (!r"u'a "a## ) Fr = The s+m of Ar of all atoms present &n the form+laExample:/r of #agnes&+m ox&,e0 #g! = 2$ < 1" = $=/r of 1o,&+m chlor&,e0 2al = 2. < .>(> = >8(>1( The relat&ve molec+lar mass of a molec+le &s'''''''''''''''''''''''''''''''''''''''( )hen compare, )&th 1/12of the mass of one atom of '''''''''''''''''2( alc+late the relat&ve molec+lar masses of the s+bstances &n the table belo)(1+bstance #olec+lar form+la %elat&ve molec+lar mass0 #r6-,rogen gas 62 2(1) = 25ropane .68Ethanol 26>!69rom&ne gas 9r2#ethane 6$?l+cose "612!"Ammon&a 26.@%elat&ve atom&c mass : 601A 012A !01"A 9r08= A 201$ B.( alc+late the relat&ve form+la masses of the follo)&ng &on&c compo+n,s &n the table(

1+bstance ompo+n, form+la %elat&ve form+la mass0 /r5otass&+m ox&,e 72! 2(.:) < 1" = :$Al+m&n&+m s+lphate Al2(1!$). 2(2C)=6-,rate, so,&+m carbonate2a2!.(1=62!1o,&+m h-,rogen s+lphate2a61!$Al+m&n&+m chlor&,e All.opper(33) s+lphate +1!$8&nc carbonate 8n!.5otass&+m carbonate72!.@%elat&ve atom&c mass: !01"A 012A 601A 70.: A +0"$ A 8n0 ">A l0 .>(> A Al0 2C10.2 A a0 $=A 2a02.A 20 1$B,THE MOLE AND THE NUM,ER OF PARTICLESLearning Out!"e#You should be able to: define a mole as the amount of matter that contains as many particles as the number of atoms in 12 g of 12C, state the meaning ofAvogadro constant, relate the number of particles in one mole of a substance with the Avogadro constant, solve numerical problems to convert the number of moles to the number of particles of a given substance and vice versa.3 F4 Chemistry Chapter 3 : Chemical Formulae and EquationsAti$it% 3 (refer text book pg .= )1( To ,escr&be the amo+nt of atoms0 &ons or molec+les 0 mole &s +se,(2( A mole &s an amo+nt of s+bstance that conta&ns as man- part&cles as the ''''''(('''''''''''''''''''''''(( &n exactl- 12g of carbon-12(.( A mole &s an amo+nt of s+bstance)h&chconta&nsa constant n+mber of part&cles atoms0 &ons0 molec+les )h&ch &s "(=2 x 1= 2.$( The n+mber "(=2 x 1=2. &s calle,'''''''''''''' (2A)>( 3n other )or,s: 1 mol of atom&c s+bstance conta&ns '''''''''''( atoms 1 mol of molec+lar s+bstance conta&ns '''''''''''( molec+les 1 mol of &on&c s+bstance conta&ns '' '''''''''''(( form+la +n&ts"( %elat&onsh&p bet)een n+mber of moles an, n+mber of part&cles (atom/&on/molec+les): x Avoga,ro onstantAvogadro Constant

2+mber of moles 2+mber of part&cles =(>mol of carbon atoms '''''''''''''' atoms of carbon =(2 moles of h-,rogen gas ( 62) (&) ''''''''''((molec+les of h-,rogen gas(&&) '''''''''''(Atoms of h-,rogen 2 mol of carbon ,&ox&,e molec+les ''''''x 1= 2. molec+les of carbon ,&ox&,e gas conta&ns :''''''( atoms ofan, '''''''(atoms of !

n+mber of moles

n+mberof part&cles

F4 Chemistry Chapter 3 : Chemical Formulae and Equations=(==C mol of calc&+m &ons '''''''''calc&+m &ons''''''''''( mol of)ater "(=2 x1= 2> molec+lesof )ater =($ molof oDone gas ( !.) '''''''(x 1= 2. molec+les of oDone0 conta&ns :''''''''' atoms of !x-gen( C( omplete these sentences (a)1 mol of calc&+m conta&ns''''''''''''''''(( atomsb)2 mol of &ron conta&ns''''''''''''''''''((atomsc)2 mol ofmagnes&+m ox&,e0 (#g!)conta&ns''''''''''''''''(( &ons,)2 mol ofso,&+m carbonate0 (2a2!.) conta&ns '''''''''''''''(e). mol of carbon ,&ox&,e0 (!2) conta&ns''''''''''''''(( molec+les f) =(> mol opper (33) n&trate0+(2!.)2 conta&ns '''''''''''''(( +2< &ons an, '''''''''''''''''''( 2!.- &onsC NUM,ER OF MOLES AND MASS OF SU,STANCES Learning Out!"e# You should be able to: state the meaning of molar mass, relate molar mass to the Avogadro constant, relate molar mass of a substance to its relative atomic mass or relative molecular mass, solve numerical problems to convert the number of moles of a given substance to its mass and vice versa.Ati$it% - (refer text book pg .. ) 1( The molar mass of a s+bstance= The molar massof EEEEEEEEEEEEEEEEE mole of the s+bstance(=The mass of (2A) n+mber of part&cles=The mass ofEEEEEEEEEEEEEEEEEEEE part&cles! F4 Chemistry Chapter 3 : Chemical Formulae and Equations x#olar mass

2( alc+lat&ng the #ass from a n+mber of#oles2+mber of moles = ( mass of the s+bstance(#ass of 1 mole of the s+bstanceT.ere(!re :#ass of s+bstance = 2+mber of moles x #assof 1moleExample 1 :;hat &s the mass of2 moles of carbon F#ass=2 x12= 2$gExample 2 : ;hat &s the mass of 2 moles of 62! F#ass = 2 x@ 2(1) moles ofox-gengas (!2)#ass = e) =(1 molesof so,&+m#ass =f) 2 moles of chlor&ne molec+les(l2)#ass =g) 1 mole of carbon ,&ox&,e ( !2)#ass = h) . moles of n&tr&c ac&,0 ( 62!. )#ass = &) 2 moles of calc&+m carbonate (a!. )#ass = G) =(2> moles of calc&+m chlor&,e (al2 )#ass ="#um$er of moles Mass in g Molar mass F4 Chemistry Chapter 3 : Chemical Formulae and Equationsk) =(2> moles of so,&+m h-,rox&,e (2a!6)#ass = l) =(2> moles of so,&+m carbonate (2a2!.)#ass =m) =(> moles of potass&+m manganate (H33) (7#n!$)#ass = n) =(2> moles of h-,rate, magnes&+m s+lphate (#g1!$(C62!)#ass = Ati$it% /$( alc+late the 2+mber of #oles from a g&ven #assExample : 6o) man- moles are there &n 88g of!2 2+mber of moles= 88= 2 moles$$a) 2g of hel&+m atoms2+mber of moles=b) "g of carbon atoms2+mber of moles=c) 1"g of hel&+m atoms2+mber of moles=,) $g of s+lph+r atoms2+mber of moles=e) $g of ox-gen molec+les (!2)2+mber of moles=f) 21.g of chlor&ne molec+les (l2)2+mber of moles=g) =(>"g of n&trogenmolec+les (22)2+mber of moles=h) 2>$g of &o,&ne molec+les (32)2+mber of moles=&) 88g of carbon ,&ox&,e (!2)2+mber of moles=G) .(1g of s+lph+r ,&ox&,e (1!2)2+mber of moles=k) >"=g of potass&+m h-,rox&,e (7!6)2+mber of moles=l) .:2g of s+lph+r&c ac&, (621!$)2+mber of moles=% F4 Chemistry Chapter 3 : Chemical Formulae and Equationsm) 1C=g of ammon&a (26.)2+mber of moles=n) 12=g of magnes&+m ox&,e (#g!)2+mber of moles=o) $g of so,&+m h-,rox&,e (2a!6)2+mber of moles=p) C.g of h-,rogen chor&,e (6l)2+mber of moles=I) 1>(8g of potass&+m manganate (H33) 7#n!$ 2+mber of moles=r) 8g of ammon&+m n&trate (26$2!.)2+mber of moles=s) =(C8g of al+m&n&+m h-,rox&,eAl(!6). 2+mber of moles=t) =(:2g of ethanol (26>!6)2+mber of moles=Ati$it% 0>( omplete the follo)&ng table(Element/compo+n,hem&calform+lae #olar mass alc+lateopper + %A#= "$ (a)#ass of 1 mol = '''''g(b) #ass of 2 mol = ''''( g(c)#ass of J mol= ''''(g(,)#ass of .(=1x1=2. + atoms=1o,&+m h-,rox&,e 2a!6 %/#= $= (a) #ass of . mol of so,&+m h-,rox&,e= (b) 2+mber of moles of so,&+m h-,rox&,e &n2= g = 8&nc n&trate 8n(2!.)2 %/# = a) 2+mber of moles &n .C(8 g of D&nc n&trate :& F4 Chemistry Chapter 3 : Chemical Formulae and EquationsDNUM,ER OF MOLES AND VOLUME OF 1ASLearning OutcomesYou should be able to: state the meaning of molar volume of a gas, relate molar volume of a gasto the Avogadro constant, mae generali!ation on the molar volume of a gas at a given temperature and pressure, calculate the volume of gases at "#$ or room conditions from the number of moles andvice versa, solve numerical problems involving number of particles, number of moles, mass of substances and volume of gases at "#$ or room conditions.Ati$it% 2 (refer text book pg ."0 .C )1( The "!'ar $!'u"e of a gas &s ,ef&ne, as the '''''''''''''''''''('''''''''''''''''''''''(2( !ne mole of an- gas al)a-s has the ''''''''''''''''' +n,er the sametemperat+re an, press+re(.( The molar vol+me of an- gas &s *- 3"3 at''''''''''''''''''or **4- 3"3 at '''''''''''''''''(Example : 1 mol of ox-gen gas0 1 mol of ammon&a gas0 1 mol hel&+m gas an, 1 mol s+lph+r ,&ox&,e gas occ+p&es the same vol+me of 2$ ,m. at roomcon,&t&on x22($ / 2$ ,m.

x 22($/2$ ,m.22($/2$ ,m.$( alc+late the $!'u"e !( ga# &n the follo)&ng n+mbers of moles at 1T5Example : /&n, the vol+me of 1 mole of !2 gasHol+me =n+mber of moles x22($ ,m.= 1 x22($ ,m.= 22($ ,m.'#um$er of moles of gas(olume of gas F4 Chemistry Chapter 3 : Chemical Formulae and Equationsa) . moles of ox-genHol+me=b) 2 moles of 6$Hol+me =c) =(. moles of ArgonHol+me =,) =(2 moles of 1!.Hol+me =e) =(1 moles of 22Hol+me =f) 1(> mol of 22Hol+me =>( omplete the,&agram belo) ( (%efer to 5age ..0.$ K .8-hem&str- textbook) Ati$it% 5S!'$e t.e#e nu"eria' 6r!+'e"#1( ;hat &s the vol+me of =(. mole of s+lph+r ,&ox&,e gas at 1T5F@#olar vol+me: 22($ ,m. mol-1 at 1T5B (Ans: "(C2 ,m.)2( /&n, the n+mber of moles of ox-gen gas conta&ne, &n a sample of 12= cm. of the gas at room con,&t&ons(@#olar vol+me: 2$ ,m. mol-1 at room con,&t&onsB(Ans: =(==> mol)1)(olume of gas *dm3+ #um$er of moles Mass in gram#o of ,articles F4 Chemistry Chapter 3 : Chemical Formulae and Equations.( alc+late the n+mber of )ater molec+les &n := g of )ater0 62!(@%elat&ve atom&c mass: 60 1A !0 1"( Avoga,ro constant0 %A: "(=2 x 1=2. mol-1B (AnsA .(=1x 1=2$ molec+les)$( ;hat &s the vol+me of 2$ g methane 06$at 1T5F@%elat&ve atom&c mass: 60 1A 0 12( #olar vol+me: 22($ ,m. mol-1 at 1T5B(Ans: ..(" ,m.)>( 6o) man- al+m&n&+m &ons are there &n 2=($ g of al+m&n&+m ox&,e0 Al2!.F@%elat&ve atom&c mass: !0 1"A Al0 2C( Avoga,ro constant0 %A: "(=2 x 1=2. mol-(2 x =(2 x "(=2x1=2.)"( alc+late the n+mber of h-,rogen molec+les conta&ne, &n " ,m. of h-,rogen gas at room con,&t&ons(@#olar vol+me: 2$ ,m. mol-1 at room con,&t&ons Avoga,ro constant0 %A: "(=2 x 1=2. mol-1B (Ans: 1(>=>x1=2. molec+les)11 F4 Chemistry Chapter 3 : Chemical Formulae and EquationsC( /&n, the vol+me of n&trogen &n cm. at 1T5 that cons&sts of 2($=8 x 1=2. n&trogen molec+les(@#olar vol+me: 22($ ,m. mol-1 at 1T5( Avoga,ro constant0 %A: "(=2 x 1=2. mol-1B (Ans: 8(:" ,m. ) ECHEMICAL FORMULAELearning Out!"e#You should be able to state the meaning of chemical formula state the meaning of empirical formula state the meaning of molecular formula determine empirical and molecular formula of substances compare and contrast empirical formula with molecular formula solve numerical problems involving empirical and molecular formula. write ionic formula of ions construct chemical formulaf ionic compounds state names of chemical compounds using &'$AC nomenclature. use symbols and chemical formula for easy and systematic communication in the field of chemistry.ACTIVIT7 8(%efer text book pg $=)1)A Chemical formula -A representat&on of a chem&cal s+bstance +s&ng letters for'''''''''''''''an, s+bscr&pts to sho) the n+mbers of each t-pe of ''''''''((that are present &n the s+bstance(

2)omplete th&s tablehem&cal s+btance hem&calform+lae2otes;ater '''''(( 2 atoms of 6 comb&ne )&th 1 atom of !12 H21+bscr&pt sho)s 2 h&,rogen atoms &n a molec+leThe letter 6 sho)s '''''('''''( F4 Chemistry Chapter 3 : Chemical Formulae and Equations'''(( 26. ''( atoms of 6 comb&ne )&th 1 atom of 25ropane.68 ''(( atoms ofcomb&ne )&th ''( atoms of 6#agnes&+m ox&,e'''''(( '''''''''''''''''(''''''(( 621!$ '''''''''''''''''.)( There are t)o t-pes of chem&cal form+lae( omplete the follo)&ng:LL (mpirical )ormula Thes&mplest '''' '''(( rat&o of atoms of each '''( &n the compo+n,(LL *olecular )ormula The act+al ''''' of atoms of each''''' that are present &n a molec+le of the compo+n,%emember:(+ample:(&)ompo+n, * Ethene (&&)ompo+n, * ?l+cose #olec+lar form+la - 2H C #olec+lar form+la - " 12 "O H C Emp&r&cal form+la -(((((((((((((((((((Emp&r&cal form+la -((((((((((((((((((((Ati$it%&91 /&n, the emp&r&cal form+la of a compo+n, Example of calc+lat&on: a) ;hen &&48/ g of metal , oxide &s re,+ce, b- h-,rogen0 &943/ g of "eta' : &s pro,+ce,( /&n, the emp&r&cal form+la of metal M ox&,e @ %A#A M02=CA !01" BElementM !#ass of element(g) 1=(.> 11(:>-1=(.> 2+mber of moles of atoms 1=(.>2=C (11(:>-1=(.>)1"%at&o of moles1&mplest rat&o of molesEmp&r&cal form+la : '''' b) A certa&n compo+n, conta&ns the follo)&ng compos&t&on:2a 1>(2.N09r >2(:8N 0 ! .1(C:N0 @ %A# : !0 1"A 2a0 2.A 9r08=B (Ass+me that 1==g of s+bstance &s +se,)Element2a9r!#ass of element(g) 1>(2. >2(:8 .1(C:13#olec+lar form+la = (Emp&r&cal form+la)n F4 Chemistry Chapter 3 : Chemical Formulae and Equations2+mber of moles atoms 1>(2. 2. >2(:88= .1(C:1"%at&o of moles1&mplest rat&o of molesEmp&r&cal form+la::''''''''''''''''''(c)omplete the table belo)(ompo+n,#olec+lar /orm+la Emp&r&cal form+la Hal+e of n;ater62!arbon O&ox&,e!2 !21+lph+r&c Ac&, 621!$Ethene26$ 629enDene"6"?l+cose"612!",) 2(>2g of a h-,rocarbon conta&ns 2(1" g of carbon( The relat&ve molec+lar mass of the h-,rocarbon &s 8$( @%A# 601A 012B &( /&n, the emp&r&cal form+la of the h-,rocarbon&&( /&n, the molec+lar form+la of the carbon(Ati$it% &&:C.e"ia' F!r"u'a (!r i!ni !"6!un3#:omplete the table belo) :at&on/orm+la An&on /orm+la6-,rogen &on+H/lo+r&,e &onF4&th&+m &on hlor&,e &on1o,&+m &on 9rom&,e &on5otass&+m &on 3o,&,e &on#agnes&+m &on 6-,rox&,e &on1 F4 Chemistry Chapter 3 : Chemical Formulae and Equationsalc&+m &on+ 2Ca2&trate &on9ar&+m &on+ 2Ba#anganate(H33) &onopper(33) &on Ethanoate &onCOO CH33ron(33) &on 2O3ron (333) &on 1+lphate &on4ea, (33) &on 1+lph&,e &on 2S8&nc &on arbonate &onhrom&+m (333) &on O&chromate (H3) &on 2% 2O CrAl+m&n&+m &on+ 3Al 3

POAmmon&+m &on hromate (H3) &onA$ti$it% &*a) hem&cal form+la of an &on&c compo+n, compr&s&ng of the &ons Mm< an, Pn- &s constr+cte, b-exchang&ng the charges of each element( The form+la obta&ne,)&ll MnPm Example :1o,&+m ox&,e opper (33) n&trate 2a