8/17/2019 Chemical Chem Reactions

1/4

You need a periodic table of elements for this. Depending on the group that each element

is in, you can find out how many electrons it gains or loses. If it is in the first group, it

will lose 1 electron. second, group, 2 electrons. And so on. The line that dividesnonmetals from metals it!s the diagonal line near the top right of the table" tells you

whether it gains or loses. To the left of that loses, and to the right of the line gains

electrons. The far right group stays the same. They are the #oble gases and are the moststable. Therefore in order to become stable, elements will either gain or lose electrons in

order to have the same electron configuration. The atom will gain or lose depending on

how much energy it ta$es to do so. It goes with the path that ta$es the least energy. Thisis what the line tells you, whether it is easier to lose electrons to become stable, or to gain

electrons to become stable.

1.SYNTHESIS REACTIONS Also known as a composition reaction, asynthesis reaction is a reaction in which two or more substances combine to form a newcompound.It is represented by the general equation

A ! " à A" #here A and " $an be ele%ents or $o%pounds and

A" is a $o%pound.

E&a%ples o' synthesis rea$tions in$lude• Synthesis o' sodiu% $hloride

Na(s) ! Cl(g) à• Synthesis o' %agnesiu% o&ide

*g(s) ! O+(g) à

• Synthesis o' #ater

H+(g) ! O+(g)à

+. ,ECO*-OSITION REACTION A decomposition reaction is the reverse of asynthesis reaction and is a reaction in which asingle compound undergoes a reaction that produces two or more simpler substances.It is represented by the general equation

A" à A ! "

http://jchemed.chem.wisc.edu/jcesoft/cca/cca0/MOVIES/NACL1.htmlhttp://jchemed.chem.wisc.edu/jcesoft/cca/cca0/MOVIES/NACL1.html

8/17/2019 Chemical Chem Reactions

2/4

  #here A" is the $o%pound and and A and " $an beele%ents or $o%pounds.

  *ost de$o%position rea$tions tae pla$e only #henenergy in the 'or% o' 

  ele$tri$ity or heat is added.E&a%ples o' de$o%position rea$tionsin$lude

• ,e$o%position o' #ater

H+O(l) à 

• ,e$o%position o' lead (II) $arbonate

-bCO/(s) à

• ,e$o%position o' sodiu% iodide

NaI(s) à

/. SIN0E2RE-ACE*ENT REACTIONS A single-replacement reaction, or displacement reaction, is a reaction in which one elementreplaces a similar element in a compound.It is represented by the general equation:

A ! 3" à A" ! 3

Or Y ! 3" à 3Y ! "

#here A4 34 "4 and Y are ele%ents and A"4 3"4 and3Y are $o%pounds.*any single2repla$e%ent rea$tions tae pla$e in#ater4 and in $o%parison to both synthesis andde$o%position rea$tions4 the a%ount o' energyrequired 'or a single2repla$e%ent rea$tion is s%aller .

E&a%ples o' single2repla$e%ent rea$tionsin$lude

•  Ther%ite rea$tion

Al(s) ! 5e+O/(s) à

• Rea$tion o' solid $al$iu% and #ater

Ca(s) ! H+O(l) à 

• Rea$tion o' solid lithiu% and $hlorine gas

http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/027_ElectroWater.MOVhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/019_THERMITE.MOVhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/027_ElectroWater.MOVhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/019_THERMITE.MOV

8/17/2019 Chemical Chem Reactions

3/4

i(s) ! Cl+(g) à

6. ,O73E2RE-ACE*ENT REACTIONS

 A double replacement reaction is a reaction inwhich the ions of two compounds exchange places in an aqueous solution to form two newcompounds. One o' the ne# $o%pounds that 'or% are usually apre$ipitate4 an insoluble gas that bubbles out o'solution4 or a %ole$ular $o%pound (usually #ater).

 The other $o%pound #hi$h 'or%s is usually solubleand re%ains in solution.,ouble2repla$e%ent rea$tions are represented by thegeneral equation

A" ! 3Y à AY ! 3"#here A4 "4 34 and Y in the rea$tants represent ionsand produ$ts AY and 3" represent ioni$ or %ole$ular$o%pounds.

E&a%ples o' double2repla$e%ent rea$tionsin$lude

• Rea$tions o' sil8er nitrate #ith sodiu% $hloride

and sil8er nitrate #ith sodiu% iodideAgNO/(aq) ! NaCl(aq) à

AgNO/(aq) ! NaI(aq) à

• Rea$tion o' sul'uri$ a$id and sodiu% hydro&ide

H+SO6(aq) ! NaOH(aq) à 

999There are t#o spe$ial $ases #hi$h ha8e spe$i:$ na%esgi8en to the%.999

1. ;hen the rea$tion is bet#een t#o ioni$ $o%poundsand they 'or% a pre$ipitate4 this rea$tion is also

$alled a precipitation. The :rst e&a%ples gi8enabo8e sho# pre$ipitation rea$tions.

+. ;hen the rea$tion is bet#een an acid  (anycompound that forms hydrogen ions) and abase (any compound that forms hydroxideions)4 #ater is 'or%ed as one o' the produ$ts. This is

http://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/072_PrecipitaReact.MOVhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/072_PrecipitaReact.MOVhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/072_PrecipitaReact.MOVhttp://cwx.prenhall.com/petrucci/medialib/media_portfolio/text_images/072_PrecipitaReact.MOV

8/17/2019 Chemical Chem Reactions

4/4

$alled neutraliation. An e&a%ple o' aneutraliO+ %i&ture

H+(g) ! O+(g) à

• 3urning o' %ethane (a hydro$arbon)

CH6(g) ! O+(g) à

• 3urning o' he&ane (a hydro$arbon)

C?H16(l) ! O+(g)à 

999Typi$ally4 $o%bustion rea$tions o$$ur #henhydro$arbons rea$t #ith o&ygen to produ$e $arbondio&ide and #ater4 and #ill ha8e the generalequation

C&Hy ! O+ à CO+! H+O#here & represents the nu%ber o' $arbon ato%s and y thenu%ber o'

hydrogen ato%s in the hydro$arbon

Hydro$arbons are a $lass o' $o%pounds thatpri%arily $onsist o' hydrogen and $arbon.999

http://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.htmlhttp://www.chem.leeds.ac.uk/delights/animations/balloons.html