unit 8 notes key
Period
Name
CRHS Academic Chemistry
UNIT 8- Chemican Reactions
NOTES
Quiz Date
Exam Date
Lab Dates Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website: ÿncochem.pbworks. corn
Page 2 of 16
Unit 8 Reactions
8.1 REACTIONS AND SKELETAL EQUATIONS
f Chemical Reactions a group of substances into a ÿ group of substances,
A chemical reaction is a process that
Evidence of a Chenÿical Change - (not proof, iust evidenceÿ
1, /-/ÿ(iÿ' lÿ exchange (temperature change, emission of light) han eio'
3, Production of ('j.-iÿ :ÿ 4, Formation of a
(odor, bubbles)
ÿ!, (ÿ,(ÿ,I
i ':'ÿ
Precipitate: an insoluble product of a chemical reaction, usually a solid.
Chemical Equations on paper.
o A chemical equation is a way to write a "ÿ They can give us a great deal of information: -i ÿ:: ÿ'ÿ ÿ!iÿ:-'ÿ o The substances that ! ...... ÿ,ÿ .1
o The substances 'I: i)ÿ o The number of
- REACTANTS - PRODUCTS
; Iÿ:ÿ ÿ ..... of each substance
o A chemical equation is NOT like a math equation,
Reactants Products
PRODUCTS
Chemical Equations Can Be Written 3 Ways:
1) ÿ/ÿ (ÿ)(i, } !iÿ 'iÿÿ Equation (this is why naming IS critical!) o The equation in •ÿ'2 ÿ.'!. [/!J Example:
P
../ÿ" •
form
Solid sodium metal reacts with oxygen gas and yields solid sodium oxide and heat,
Page 3 of :[6
Unit 8 Notes
f
I! Equation
2)
; f,
....
Formulas written but / balanced (no coefficients) Example: Na(s) + 02 (g) ÿ Na20 (sl + heat
o Formulas written and balanced 4 Na(s) + :I 02(ÿ)-ÿ _ÿ2 Na20 (s)+ heat
Example:
Sÿmbols - in writing reactions, we use many common symbols to indicate components of the reaction. See
also: the cover[
Symbol
Symbol Meaning
Meaninÿ
+
\
separates reactants & products
A
• :
solid phase
yields or produces
liquid phase
heat is added
gaseous phase
reaction is reversible
To show a catalyst is added (ex: MnO2), write:
It
dissolved in water
MnOÿ
The Law of Conservation of Mass o The Law of Conservation oÿMass (LoCoM) states that matter cannot be created or destroyed, In equation form:
%
Mass of
= Mass of
,
....
ÿ
/ ÿ: ÿ
'ÿ
Equations must be balanced because of the Law of Conservation of
Page 4 of 16
Unit 8 Reactions
f!: '
o So, there must be an EÿUAL number of atoms of each element on ;
of the
chemical equation.
x
Writing Skeletal Eguations
1)
) ÿ (-'% t'ÿ" ! i{' compounds use prefixes (mono, di, tri, etc...), contain 2 or more nonmetals, and do not need to be "criss-crossed". Example: ...carbon dioxide g.ÿ =
2)
Any / .ÿ .t.ÿ,ÿ ÿ !ÿ(,
f? f , ( .......... l.,) ._.ÿ
compound (with polyatomic ion or transition metal) or acid must have charge
numbers criss-crossed to find the proper subscripts.
Example: ... solid lithium oxide = (Li+1 0-2)
, ÿ,
(I 1 (ÿ/
are written by themselves UNLESS they are diatomic molecules (H2, 02,
3) Single
F2, Br2, 12, N2, CI2). If diatomic, add a 2 subscript. Examples: ,,.ÿ =
4)
Include the
ÿ'\ ,I" V i} ÿi
.
"
for the state of matter. Keep in mind that a "crystal" or "metal" is
a
5)
The "reaction action" words tell you where the
goes. (produce, yield, make, form,
creates,.,)
Example Liquid ammonia (NH3) and oxygen gas burn to form nitrogen monoxide gas and water,
!': / t
I¸ €,
Unit 8 Notes
Page 5 of 16
Practice Carbon monoxide gas reacts with oxygen gas to produce carbon dioxide gas.
Iron (III) oxide crystals react with gaseous carbon monoxide to form iron metal and carbon dioxide gas.
( t
;
i'"
)'
'
Potassium chlorate crystals decompose to yield solid potassium chloride and oxygen gas.
.)
Liquid bromine and potassium iodide in solution react to form liquid iodine and potassium bromide in solution
f
ÿf+ ,+ -
When ignited, gaseous methane (CH4) reacts with oxygen gas to form water vapor and carbon dioxide gas.
' >!
.
t)
, /,*"
Page 6 of 16
Unit 8 Reactions
8.2 BALANCING CHEMICAL EQUATIONS
Balancing Chemical Equations - There are two types of numbers in a chemical equation. o .... ,:, (;,'l[ÿ
= the number of atoms of one part of a compound. Applies only to the I
element/polyatomid ion it follows, I I I
4 Na(s) + Oÿ(g) ÿ> 2 Na20(s ' " , =:menumber of atoms of the element or compound that it comes before. Applies to the entire substance.
Steps to Balancing Skeletal ÿuations
/
1. Makea ¢'over from reactants!
* Do NOT bringÿ'ÿ
+
Practice - predict the products and balance k :, : .C4Hlo(g) +__;
02(g) --> ÿ
' : f :
+
!/
Page 10 of 16
Unit 8 Reactions
B, A SINGLE REPLACEMENT reaction is one in which (ÿ(f](!-element takes the place of
SINGLE REPLACEMENT REACTION
o The reactants willbe an
or
, ÿletal (;ÿ! Lithium , Potassium
o A single metal will replace a Dÿ )f'j; 1iÿ:ÿ!' !?;ÿ..
Barium Caldunl Sodium [,lagnesltlm
e A halogen will replace a o Replacement reactions are
Aluminum blanganese
reversible,
Zinc Chromium Iron Cobalt Nlckel Tin Lead (Hydrogen)
Q: How do we know ira reaction will occur? 1
A: We use the ( !)-f i'
ÿ': for metals and
Copper blercury Silver Platinum
for halogens.
Gold
17 7A 9
F 1#.'ÿ-ÿ#
17
Cl G,$r_,3 Gh',:- ÿ,:ÿ
PREDICT the PRODUCTS of a Sinÿlacement Reaction:
s 1
2.
Find the f() (ÿ 1,(::y element in the reactants (metal/halogen) Compare to the
t::*, element in the ionic compound on the activity series
5.
Halogens can replace halogens
or
I 8S
Metals can only replace metals that are __ active, or them on the activity series.
,
7g.N34
126.€Nÿ Icdn;ÿ
group 17 (halogens) ,
Br
them in group 17,
If the lone element !" replace it's like element in the compound, write "NR" as the product for "no reaction".
6. IfitCAN replace: -ÿ, ,:, >, co form the new ionic compound,
b, Write the new lone element. Don't forget HOFBrlNCI!
At
Unit g Notes
Example - predict products and balance
1.
Ba (s) +
ÿ:' ZnNO3 (aq) -ÿ
2. ÿ CI2 (g) + __ LiBr (aq) -ÿ
3, __ Na (s) + __ KBr (aq) -ÿ Practice - predict products and balance
1. Fe (S) + MgS04 (aq) 2. ' ' Br2 (I) + ÿ::' AII3 (aq) -ÿ &-&
3. Ca (s) +
CuSO4 (aq) --ÿ
Paÿe 3.11 of 1(i
Page 12 of 16
Unit 8 Reactions
8.5 DOUBLE REPLACEMENT REACTIONS: PRECIPITATION & ACID-BASE A DOUBlE-REPLACEMENT reaction is a reaction in which two ionic compounds in solution swap
.>i(ÿi'i'[lS[:'(ÿ. and forms 2 new ionic compounds, %
#
ÿ- '
DOUBLE REPLACEMENT REACTION]
o The cation from one compound joins the anion from the other and vice versa, o There are 2 Types: Precipitation Reactions and Aÿd-Base Reactions
{ ,BaCI2 (aq) +
\
,/
(71,/'\'') (')'','7
)? ( 7,,
Li2CO3 (aq) --)' /'
I' /
/
/
" :; , } /
%.
Practice - predict products and balance ,) %
1.
Ah(S04)3 (aq) + .... Ca(OH)2 (aq) -->
2, ":i! CaI? (aq) + "/" K3PO4 (aq) ---> /( I('0 W
\ t
"%
Unit g Notes
Page 13 of 16
2, ACID-BASE REACTIONS A special type of double replacement reaction in which an acid and base combine, There IS NO
"
' {ÿ
/
ACID-BAÿ;E REACTION
o The reactants are: The products are:
',
|
ÿ - ends with ( !\,ÿsÿ,:'; .
Practice - predict products and balance HNO3 (aq) 4- Ba(OH)2 (aq) -'->
+
Page 14 of 16
Unit 8 Reactions
Extra Credit o Balancing Challenge: Balance the [ollowing reactions 1. __(NH4) 2C03
2. __HN03
3.
+ HI
KMn04 +
4.
NH3 +
5.
KI04 +
10.
ÿ
02 ÿ
NO +
KI +
Li+
C8Hÿ8
02
N2
+
C02
+
MnC12 +
"ÿ
I2
+
C12 +
KCI +
__Sb20s +
"ÿ
+ H20
H2'
H20 +
I2 +
NO + H20
K3Fe(SCN)6 +
__ Fe203
H20
+
K2S04
502
Li3N
02
KC1
H20
HCI ÿ
HN03
+
+
NO3
Fe2(S04)3 + KSCN -)
8. FeS2
9.
NH3
HC1
6. __ Sb +
7.
ÿ
C02
+
H20
Unit g Notes
i;{ÿl
I,I
Name acetate
Ion NH4+1
carbonate
CO32
chlorite
Name
C2H302-1 or CH3COO-1
ammonium
chlorate
Page 15 of 116
CIO3-ÿ C102-ÿ
Ion
hypochlorite nitrate nitrite
ÿ
perchlorate permanganate
CIO-ÿ NO3-1
Lithium
NO2-1
Potassium
CIO4-1
Barlu ill
Mn04-1
Calcium Sodium
chromate
Cr042
phosphate
P04"3
cyanide
CN-ÿ
phosphite
PO3-3
dichromate
Cr2072
hydrogen carbonate
HC03-ÿ
hydroxide
OH-ÿ
silicate sulfate sulfite
Metal
SiO32 S04"2 S032
Magnesiu Ill
AI umhlu m Manganese
Zinc C:hromlLlm Iron
Coba It _Soluble
Common exceptions
Tin
_compounds contain
C2H30ÿ, CH3CO0-
Nickel
None
Lead (Hydrogen)
NH4
None
NO3-
None
CN-
None
CIO-
None
Platinum
CIO2
None
Gold
CIOÿ-
None
CIO4
None
Br-
Compounds of Ag+, Pb2+, and Hgÿ+
CI-
Compounds of Ag+, Pb2+, and Hgÿ+
1-
Compounds of Ag+, Pb2+, and Hgÿ+
SOÿ-
Compounds of Sr2+, Ba2+, Pb2+, and Hg22÷
Insoluble
Common exceptions
COÿ-
Compounds of NH+ and the alkali metal cations
POÿ-
Compounds of NH+ and the alkali metal cations
CrOÿ-
Compounds of NH4 and the alkali metal cations
Cr2072OH-
Compounds of NH+ and the alkali metal cations Compounds of NH4, the alkali metal cations, Ca2+, SF2+, and Ba2+
S2-
Compounds of NH4, the alkali metal cations, Ca2+, SF2+, and Ba2+
Copper M ere u ry
StlveF
Page 16 of 16
Unit 8 Reactions
fÿ ,ÿ,,
oj
ÿ.ÿ = e, :i
mÿ
d tÿ co
e,I O
C
,
ÿ:-
'73 ÿ
4
Oÿ o
,ÿ
E
E
[;
,l!
.,ÿ
=
a
ÿ-ÿ
C9
O9
Name
CRHS Academic Chemistry
UNIT 8- Chemican Reactions
NOTES
Quiz Date
Exam Date
Lab Dates Notes, Homework, Exam Reviews and Their KEYS located on CRHS Academic Chemistry Website: ÿncochem.pbworks. corn
Page 2 of 16
Unit 8 Reactions
8.1 REACTIONS AND SKELETAL EQUATIONS
f Chemical Reactions a group of substances into a ÿ group of substances,
A chemical reaction is a process that
Evidence of a Chenÿical Change - (not proof, iust evidenceÿ
1, /-/ÿ(iÿ' lÿ exchange (temperature change, emission of light) han eio'
3, Production of ('j.-iÿ :ÿ 4, Formation of a
(odor, bubbles)
ÿ!, (ÿ,(ÿ,I
i ':'ÿ
Precipitate: an insoluble product of a chemical reaction, usually a solid.
Chemical Equations on paper.
o A chemical equation is a way to write a "ÿ They can give us a great deal of information: -i ÿ:: ÿ'ÿ ÿ!iÿ:-'ÿ o The substances that ! ...... ÿ,ÿ .1
o The substances 'I: i)ÿ o The number of
- REACTANTS - PRODUCTS
; Iÿ:ÿ ÿ ..... of each substance
o A chemical equation is NOT like a math equation,
Reactants Products
PRODUCTS
Chemical Equations Can Be Written 3 Ways:
1) ÿ/ÿ (ÿ)(i, } !iÿ 'iÿÿ Equation (this is why naming IS critical!) o The equation in •ÿ'2 ÿ.'!. [/!J Example:
P
../ÿ" •
form
Solid sodium metal reacts with oxygen gas and yields solid sodium oxide and heat,
Page 3 of :[6
Unit 8 Notes
f
I! Equation
2)
; f,
....
Formulas written but / balanced (no coefficients) Example: Na(s) + 02 (g) ÿ Na20 (sl + heat
o Formulas written and balanced 4 Na(s) + :I 02(ÿ)-ÿ _ÿ2 Na20 (s)+ heat
Example:
Sÿmbols - in writing reactions, we use many common symbols to indicate components of the reaction. See
also: the cover[
Symbol
Symbol Meaning
Meaninÿ
+
\
separates reactants & products
A
• :
solid phase
yields or produces
liquid phase
heat is added
gaseous phase
reaction is reversible
To show a catalyst is added (ex: MnO2), write:
It
dissolved in water
MnOÿ
The Law of Conservation of Mass o The Law of Conservation oÿMass (LoCoM) states that matter cannot be created or destroyed, In equation form:
%
Mass of
= Mass of
,
....
ÿ
/ ÿ: ÿ
'ÿ
Equations must be balanced because of the Law of Conservation of
Page 4 of 16
Unit 8 Reactions
f!: '
o So, there must be an EÿUAL number of atoms of each element on ;
of the
chemical equation.
x
Writing Skeletal Eguations
1)
) ÿ (-'% t'ÿ" ! i{' compounds use prefixes (mono, di, tri, etc...), contain 2 or more nonmetals, and do not need to be "criss-crossed". Example: ...carbon dioxide g.ÿ =
2)
Any / .ÿ .t.ÿ,ÿ ÿ !ÿ(,
f? f , ( .......... l.,) ._.ÿ
compound (with polyatomic ion or transition metal) or acid must have charge
numbers criss-crossed to find the proper subscripts.
Example: ... solid lithium oxide = (Li+1 0-2)
, ÿ,
(I 1 (ÿ/
are written by themselves UNLESS they are diatomic molecules (H2, 02,
3) Single
F2, Br2, 12, N2, CI2). If diatomic, add a 2 subscript. Examples: ,,.ÿ =
4)
Include the
ÿ'\ ,I" V i} ÿi
.
"
for the state of matter. Keep in mind that a "crystal" or "metal" is
a
5)
The "reaction action" words tell you where the
goes. (produce, yield, make, form,
creates,.,)
Example Liquid ammonia (NH3) and oxygen gas burn to form nitrogen monoxide gas and water,
!': / t
I¸ €,
Unit 8 Notes
Page 5 of 16
Practice Carbon monoxide gas reacts with oxygen gas to produce carbon dioxide gas.
Iron (III) oxide crystals react with gaseous carbon monoxide to form iron metal and carbon dioxide gas.
( t
;
i'"
)'
'
Potassium chlorate crystals decompose to yield solid potassium chloride and oxygen gas.
.)
Liquid bromine and potassium iodide in solution react to form liquid iodine and potassium bromide in solution
f
ÿf+ ,+ -
When ignited, gaseous methane (CH4) reacts with oxygen gas to form water vapor and carbon dioxide gas.
' >!
.
t)
, /,*"
Page 6 of 16
Unit 8 Reactions
8.2 BALANCING CHEMICAL EQUATIONS
Balancing Chemical Equations - There are two types of numbers in a chemical equation. o .... ,:, (;,'l[ÿ
= the number of atoms of one part of a compound. Applies only to the I
element/polyatomid ion it follows, I I I
4 Na(s) + Oÿ(g) ÿ> 2 Na20(s ' " , =:menumber of atoms of the element or compound that it comes before. Applies to the entire substance.
Steps to Balancing Skeletal ÿuations
/
1. Makea ¢'over from reactants!
* Do NOT bringÿ'ÿ
+
Practice - predict the products and balance k :, : .C4Hlo(g) +__;
02(g) --> ÿ
' : f :
+
!/
Page 10 of 16
Unit 8 Reactions
B, A SINGLE REPLACEMENT reaction is one in which (ÿ(f](!-element takes the place of
SINGLE REPLACEMENT REACTION
o The reactants willbe an
or
, ÿletal (;ÿ! Lithium , Potassium
o A single metal will replace a Dÿ )f'j; 1iÿ:ÿ!' !?;ÿ..
Barium Caldunl Sodium [,lagnesltlm
e A halogen will replace a o Replacement reactions are
Aluminum blanganese
reversible,
Zinc Chromium Iron Cobalt Nlckel Tin Lead (Hydrogen)
Q: How do we know ira reaction will occur? 1
A: We use the ( !)-f i'
ÿ': for metals and
Copper blercury Silver Platinum
for halogens.
Gold
17 7A 9
F 1#.'ÿ-ÿ#
17
Cl G,$r_,3 Gh',:- ÿ,:ÿ
PREDICT the PRODUCTS of a Sinÿlacement Reaction:
s 1
2.
Find the f() (ÿ 1,(::y element in the reactants (metal/halogen) Compare to the
t::*, element in the ionic compound on the activity series
5.
Halogens can replace halogens
or
I 8S
Metals can only replace metals that are __ active, or them on the activity series.
,
7g.N34
126.€Nÿ Icdn;ÿ
group 17 (halogens) ,
Br
them in group 17,
If the lone element !" replace it's like element in the compound, write "NR" as the product for "no reaction".
6. IfitCAN replace: -ÿ, ,:, >, co form the new ionic compound,
b, Write the new lone element. Don't forget HOFBrlNCI!
At
Unit g Notes
Example - predict products and balance
1.
Ba (s) +
ÿ:' ZnNO3 (aq) -ÿ
2. ÿ CI2 (g) + __ LiBr (aq) -ÿ
3, __ Na (s) + __ KBr (aq) -ÿ Practice - predict products and balance
1. Fe (S) + MgS04 (aq) 2. ' ' Br2 (I) + ÿ::' AII3 (aq) -ÿ &-&
3. Ca (s) +
CuSO4 (aq) --ÿ
Paÿe 3.11 of 1(i
Page 12 of 16
Unit 8 Reactions
8.5 DOUBLE REPLACEMENT REACTIONS: PRECIPITATION & ACID-BASE A DOUBlE-REPLACEMENT reaction is a reaction in which two ionic compounds in solution swap
.>i(ÿi'i'[lS[:'(ÿ. and forms 2 new ionic compounds, %
#
ÿ- '
DOUBLE REPLACEMENT REACTION]
o The cation from one compound joins the anion from the other and vice versa, o There are 2 Types: Precipitation Reactions and Aÿd-Base Reactions
{ ,BaCI2 (aq) +
\
,/
(71,/'\'') (')'','7
)? ( 7,,
Li2CO3 (aq) --)' /'
I' /
/
/
" :; , } /
%.
Practice - predict products and balance ,) %
1.
Ah(S04)3 (aq) + .... Ca(OH)2 (aq) -->
2, ":i! CaI? (aq) + "/" K3PO4 (aq) ---> /( I('0 W
\ t
"%
Unit g Notes
Page 13 of 16
2, ACID-BASE REACTIONS A special type of double replacement reaction in which an acid and base combine, There IS NO
"
' {ÿ
/
ACID-BAÿ;E REACTION
o The reactants are: The products are:
',
|
ÿ - ends with ( !\,ÿsÿ,:'; .
Practice - predict products and balance HNO3 (aq) 4- Ba(OH)2 (aq) -'->
+
Page 14 of 16
Unit 8 Reactions
Extra Credit o Balancing Challenge: Balance the [ollowing reactions 1. __(NH4) 2C03
2. __HN03
3.
+ HI
KMn04 +
4.
NH3 +
5.
KI04 +
10.
ÿ
02 ÿ
NO +
KI +
Li+
C8Hÿ8
02
N2
+
C02
+
MnC12 +
"ÿ
I2
+
C12 +
KCI +
__Sb20s +
"ÿ
+ H20
H2'
H20 +
I2 +
NO + H20
K3Fe(SCN)6 +
__ Fe203
H20
+
K2S04
502
Li3N
02
KC1
H20
HCI ÿ
HN03
+
+
NO3
Fe2(S04)3 + KSCN -)
8. FeS2
9.
NH3
HC1
6. __ Sb +
7.
ÿ
C02
+
H20
Unit g Notes
i;{ÿl
I,I
Name acetate
Ion NH4+1
carbonate
CO32
chlorite
Name
C2H302-1 or CH3COO-1
ammonium
chlorate
Page 15 of 116
CIO3-ÿ C102-ÿ
Ion
hypochlorite nitrate nitrite
ÿ
perchlorate permanganate
CIO-ÿ NO3-1
Lithium
NO2-1
Potassium
CIO4-1
Barlu ill
Mn04-1
Calcium Sodium
chromate
Cr042
phosphate
P04"3
cyanide
CN-ÿ
phosphite
PO3-3
dichromate
Cr2072
hydrogen carbonate
HC03-ÿ
hydroxide
OH-ÿ
silicate sulfate sulfite
Metal
SiO32 S04"2 S032
Magnesiu Ill
AI umhlu m Manganese
Zinc C:hromlLlm Iron
Coba It _Soluble
Common exceptions
Tin
_compounds contain
C2H30ÿ, CH3CO0-
Nickel
None
Lead (Hydrogen)
NH4
None
NO3-
None
CN-
None
CIO-
None
Platinum
CIO2
None
Gold
CIOÿ-
None
CIO4
None
Br-
Compounds of Ag+, Pb2+, and Hgÿ+
CI-
Compounds of Ag+, Pb2+, and Hgÿ+
1-
Compounds of Ag+, Pb2+, and Hgÿ+
SOÿ-
Compounds of Sr2+, Ba2+, Pb2+, and Hg22÷
Insoluble
Common exceptions
COÿ-
Compounds of NH+ and the alkali metal cations
POÿ-
Compounds of NH+ and the alkali metal cations
CrOÿ-
Compounds of NH4 and the alkali metal cations
Cr2072OH-
Compounds of NH+ and the alkali metal cations Compounds of NH4, the alkali metal cations, Ca2+, SF2+, and Ba2+
S2-
Compounds of NH4, the alkali metal cations, Ca2+, SF2+, and Ba2+
Copper M ere u ry
StlveF
Page 16 of 16
Unit 8 Reactions
fÿ ,ÿ,,
oj
ÿ.ÿ = e, :i
mÿ
d tÿ co
e,I O
C
,
ÿ:-
'73 ÿ
4
Oÿ o
,ÿ
E
E
[;
,l!
.,ÿ
=
a
ÿ-ÿ
C9
O9
