Download unit 7 h chem notes - chemical equations

UNIT 7 H CHEM NOTES - CHEMICAL EQUATIONS
I. Chemical Reactions and their equations.
1. The materials which you can start with are written first, and are called reactants. If
there is more than one reactant, a plus (+) sign separates each individual reactant.
Example: Sodium reacts with chlorine to form sodium chloride (NaCl). An arrow is
written after the reactants.This is how the reactants would be written...
Na + Cl2 ------->
2. The product(s) are those substances which are formed or produced in the reactions.
They are always different substances than what you start with.
Na
+
Cl2
-------->
NaCl
3. If atoms are unbonded a plus sign separates them. In the above example, the plus sign
tells you that there are two reactants, and they are not bonded together.
4. To indicate the number of atoms (unbonded) or the number of molecules, you use the
coefficient. In the final equation on the left side the 2 in front of the Na indicates that 2
atoms, unbonded, of sodium were required for this reaction. The 2 in front of the sodium
chloride indicates that 2 separate molecules of sodium chloride were formed. There is an
implied 1 for the coefficient of the chlorine...
2Na
+
Cl2
--------> 2NaCl
5. If the atoms are bonded, they are not separated by a plus sign. In the example, the
product, sodium chloride, indicates that the sodium and chlorine are bonded together into a
molecule.
6. To indicate the number of each atom bonded into a molecule, a subscript is needed.
In the above example, the chlorine consists of two atoms of Cl bonded. If it had been
written 2Cl, we would still have two atoms of chlorine, but they would not be bonded
together.
7. When balancing an equation, you must be sure to have the same number of atoms of
each element on the left of the arrow as you have on the right side of the arrow. Law of
conservation of atoms: Atoms may neither be created nor destroyed. If you look at
the equation written in the number 2 above, you would note that there is ONE Na indicated
on the left, and ONE Na indicated on the right. However there are two Cl atoms on the
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
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left, but only one on the right. This form of the equations violates the above law. You
must now employ the process known as BALANCING EQUATIONS.
**** When balancing an equation you may never change the subscripts
(once the correct formula for the compounds are written). You may change
the coefficients to any number you wish in order to balance the
equation. When you think you are finished balancing, check to see if
all of the coefficients can be divided by the same number. If not, make the
correction.
Examples:
Na
+
Cl2
------->
NaCl
A. In order to balance this equation you may NOT:
1. Erase the subscript of the Cl. (Na + Cl ----> NaCl)
2. Add a subscript to the NaCl molecule to make Na Cl2
B. You should say to yourself, “I need to have two chlorine atoms on the right”.
You may put a coefficient 2 in front of the entire NaCl formula. You may not
put a 2 in between the Na and the Cl. The balanced equation reads...
Na
+
Cl2
------->
2NaCl
C. The 1 in front of the NaCl (or any coefficient in the front of a compound)
multiplies the number of all the atoms in the compound by that
number. This now means that you have one atom of sodium on the left
and TWO atoms of sodium on the right.
D. To correct this situation, which violates the law of conservation of atoms, go
back to the left side of the equation and put a 2 in front of the Na. This only
multiplies the Na by 2 since there is a plus sign separating the Na and the Cl.
The equation now reads...
2Na
+
Cl2
--------> 2NaCl
You now have 2 Na atoms on the left, and two atoms on the right side. You
also have 2 Cl atoms on the left, and two Cl atoms on the right. When
balancing equations it is not necessary to have the same number of each
element, but the number of atoms of each element on the left, must equal the
same number of atoms of that element on the right.
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II. Practice balancing chemical equations...
A. The process of rusting:
Fe
+
O2
------>
Fe2O3
B. Used as an oxygen source in explosives:
C.
KClO3
------->
O2
+
KCl
MgBr2 +
Cl2
-------->
MgCl2
+
-------->
CO2 +
H2O
------->
NaOH
+
O2
+
HCl
Br2
D. A basic fuel for high performance engines:
C2H6
+
O2
E. A solid oxidant for rocket fuels:
Na2O2
+
H2O
F.
KIO
------->
G.
NaCl
+
H2SO4
H.
Ag
+
HNO3
KI
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
+
------>
-------->
KIO3
Na2SO4
AgNO3
+
NO2 +
H2O
3
Worksheet EE H Chem Write/Balance Simple Eq.
Name________________
I. Memorize the Diatomic Elements: H2 Br2 O2 N2 Cl2 I2 F2
Mnemonic devices :
HBrONClIF
HNFOIClBr
HOClBrFIN
(havenofearoficecoldbeer)
(Huckleberry Fin)
II. Sometimes it is necessary to abbreviate the “phase” of the substance to the lower right of the substance.
Some abbreviations are: s = solid, l= liquid, g ( )= gas, aq= aqueous, ppt ( )= precipitate.
III Write equations using correct formulas of diatomic molecules, then Balance the equation for each of the
reactions.
1. Hydrogen gas reacts with chlorine gas to yield Hydrogen chloride.
2. Carbon reacts with oxygen gas to form Carbon dioxide.
3. Lithium reacts with chlorine gas to form Lithium Chloride.
4. Calcium reacts with Bromine to yield Calcium Bromide.
5. Hydrogen gas reacts with oxygen gas to yield water.
6. Water decomposes to form Hydrogen gas and Oxygen gas.
7. Carbon Dioxide decomposes to form carbon monoxide and oxygen gas.
8. Hydrogen gas reacts with nitrogen gas to yield Ammonia gas (NH3)
9. Aluminum metal reacts with oxygen gas to form Aluminum oxide.
10. Nitrogen gas reacts with Iodine to yield Nitrogen triiodide
11. zinc + chlorine ---> zinc chloride
12. sodium hydrogen carbonate ---> sodium carbonate + water + carbon dioxide
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13. sodium + iodine ---> sodium iodide
14. barium chloride + potassium sulfate ---> barium sulfate + potassium chloride
15. calcium hydroxide + ammonium sulfate ---> calcium sulfate + water + ammonia
16. silver oxide ---> silver + oxygen
17. zinc + hydrochloric acid ---> hydrogen + zinc chloride
18. sodium hydroxide + sulfuric acid ---> sodium sulfate + water
19.
C2H2 +
20. Zinc
+
O2 --->
Sulfur
CO2 +
à
H2 O
Zinc Sulfide
21. Potassium Chloride + Silver Nitrate
22. Calcium Oxide
+ water
à
à
Silver chloride + Potassium Nitrate
calcium hydroxide
23. Sodium hydroxide + hydrochloric acid à Sodium chloride + water
à
24. Aluminum + Iron III Oxide
25. Nitric Acid
à
water +
27. Hydrogen +
28. Zinc
Bromine
+
Nitrogen dioxide
à
26. Silver Nitrate + Nickel
à
sulfuric acid
Aluminum Oxide + Iron
+
oxygen
Nickel Nitrate + Silver
Hydrogen Bromide
à
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
Zinc sulfate
+ hydrogen
5
Worksheet FF H Chem
Name ___________________
I. Balance the following Equations.
+
à
CH4
H2O
à
HNO3
KI à
KBr
1.
C
H2
2.
N2O5 +
3.
Br2
+
4.
H2
+
Fe3O4
à
Fe
5.
Al
+
AgNO3
à
Al(NO3)3 +
6.
Al2(SO4)3 +
7.
FeCl3
8.
Ni(ClO3)2
9.
I2
+
NaCl
à
10.
H2
+
Br2
à
11.
H2SO4
+
12.
Sr(NO3)2 +
13.
P4
14.
Hg(OH)2
15.
C7H16 +
16.
S8
+
Ca(OH)2 à Al(OH)3 +
H2S
à
FeCl2 +
à
H2O
Ag
CaSO4
HCl
NaI
+
S
O2
+
Cl2
HBr
HOH
à
K2SO4
O2
+
NiCl2 +
à
+
I2
KNO3
à
+
SO3
+
SrSO4
P2O5
à
HgO
+
O2
à
CO2
+
+
O2
à
HOH
H2O
SO2
II. Also, for each of the 16 questions above, identify the type of reaction as either Composition,
combustion, Decomposition, single or double replacement, .
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Notes- Five General Categories of Chemical Reactions
I Composition - ( Also called Combination or Synthesis ) A complex substance is formed when two
or more smaller substances chemically combine.
General Forms:
Element
or
+
Element --------> Compound
Simple Nonionic Compound + Simple Nonionic Compound ----> Complex compound
(Covalent)
Examples:
C
+
O2
----------->
CO2
Fe
+
S
----------->
FeS
2Mg
+
O2
----------->
2MgO
NH3
+
H2 O
----------->
NH4OH
II Decomposition- A Single compound is broken into two or more smaller
substances, either elements or compounds
General Form:
ONE Complex Compound
Examples:
-------- > Simple compound +
(or element)
Simple compound
(or element)
2H2O
----------->
O2
+
2H2
** 2KClO3
----------->
2KCl +
3O2
2HgO
----------->
Hg
+
O2
** CaCO3
----------->
CaO
+
CO2
** Ternary ionic compounds must be studied further to determine HOW they break apart.
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III Single Replacement- A Reaction between an element and an ionic compound, to form a new element
and a new ionic compound. If the element reacting forms positive ions , it replaces the positive part of the
ionic compound.
If the element forms negative ions, it replaces the negative part of the compound.
General Form:
Element
+
Ionic compound
Examples:
-------> new Ionic Compound
Fe
+
CuSO4 ----------->
Cl2
+
2KI
Zn
+
H2SO4 ----------->
Cu
+
2AgNO3
FeSO4 +
----------->
----------->
Cu
2KCl
ZnSO4 +
+ new element
+
I2
+
2Ag
H2
Cu(NO3)2
IV Double Replacement- ( Also called Ionic) A Reaction between one ionic and a second ionic
compound, to form two new ionic compounds. The positive ions of the ionic compound switch
places. The negative ions ,switch places.
General Form:
ionic Compound + Ionic compound -------> new (Ionic )Compound
+ new Ionic Compound
Examples:
BaCl2
H2SO4 ----------->
BaSO4 +
2HCl
+
NaOH ----------->
NaCl
+
NaCl +
AgNO3 ----------->
NaNO3 +
AgCl
HCl
+
H2O ( HOH)
V. Combustion- ( Also called”Burning”) A Reaction between a Hydrocarbon and oxygen gas to
form carbon dioxide and water.
General Form:
Hydrocarbon(others) + oxygen gas ------->
Examples:
CH4
+
C9H18 +
CO 2
+ H2O
2O2
----------->
CO2
+
2H2O
27/2 O2
---------->
9CO2
+
9H2O
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Six Types of Decomposition Reactions
General Form:
*Complex Compound (solid) ------->
Simple + Simple
*These ARE SOLIDS and NOT aqueous compounds except for the acids!!!!!!!!!
**NOTE: Reactions for TERNARY compounds must be memorized!!!!!!!!
**1) Metallic Carbonates
+
H2 O
--------------> Metallic Chloride
+
O2
----------->
KCl
+
O2
----------->
NiCl2
+
O2
CaO
+
CO2
BaCO3
----------->
BaO
+
CO2
(s)
---------------> Metallic Oxide
Ca(OH)2 (s)
----------->
CaO
+
H2 O
Zn(OH) 2(s)
----------->
ZnO
+
H2 O
KClO3
(s)
Ni(ClO3)2 (s)
Ternary Acids (aqueous)
H2SO4
---------------> NONmetallic Oxide +
(aq)
----------->
SO3
+
H2 O
H2CO3 (aq)
----------->
CO2
+
H2 O
----------->
Metallic Oxide
----------->
CuO
*5) Metal Sulfates
CuSO4 (s)
Some Binary Oxides
HgO (s)
PbO2 (s)
7)
CO2
----------->
**3) Metallic Chlorates
6)
+
CaCO3 (s)
**2) Metallic Hydroxides
*4)
---------------> Metallic Oxide
Some Binary Compounds
H2 O
NaCl
(l)
+
+
SO3
SO3
---------------> Metal or metallic Oxide
----------->
Hg
----------->
+
O2
PbO
+
(electrolysis)--------------> element
elec----------> H2
+
O2
elec-----------> Na
+
Cl2
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
H2 O
+
O2
O2
+
element
9
Four Types of Single Replacement Reactions
General Form :
Element
+
Ionic Compound --------.>
Ionic Compound
+ Element
NOTE; Metals usually form positive ions, nonmetals form negative ions
Metallic elements will replace the positive part of the compound
Nonmetallic elements will replace the negative part of the compound
*1) Replacement of a metal by a more active metal (SEE ACTIVITY SERIES next page)
(not balanced)
Zn
+
CuSO4 ----------->
ZnSO4 +
Cu
Al
+
FeSO4 ----------->
Al2(SO4)3
+
Fe
2) Replacement of (first) Hydrogen in water (HOH) by a more active metal.
(not balanced)
Ca
+
HOH ----------->
Ca(OH)2
+
Na
+
HOH ----------->
NaOH +
H2
H2
3) Replacement of Hydrogen in acids by a more active metal
(not balanced)
Zn
+
H2SO4 ----------->
ZnSO4 +
H2
Sn
+
HNO3 ----------->
Sn(NO3)4
+
H2
4) Replacement of a halogen by a more active nonmetal
(not balanced)
Cl2
+
KBr
----------->
KCl
+
Br2
F2
+
NaCl
----------->
NaF
+
Cl2
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ACTIVITY SERIES
Most active
REACTIVITY
Li
All react
Rb
K
w/cold water
And acids
Ba
Replacing
Sr
Hydrogen
Ca
Na
Mg
All react with
Al
Acid or steam
Mn
But NOT
Zn
Cr
Liquid water
To replace Hydrogen
Fe
Cd
All react with
Co
Acids but not
Ni
Liquid water
Least active
Sn
Pb
H2
All react with
Bi
Oxygen
As
Cu
To form oxides
Hg
Ag
ALL are mostly
Pt
UNreactive
Au
HALOGENS
FLUORINE > CHLORINE> BROMINE > IODINE> SULFUR
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Worksheet GG H CHEM
Name________________
Equations- writing & balancing, Prediction of products
I. Priority #1- Write the correct formulas for each Reactant. Then try to classify the reactions as
either composition, decomposition, single or double replacement, or combustion. Try to write the
formulas of the product(s). Then balance each equation.
1. Sodium
2. Calcium
+ Iodine
+
à
à
oxygen
à
3. Nickel chlorate
4. Barium Carbonate à
5. Aluminum + hydrochloric acid à
6. Potassium Iodide + Chlorine à
7. Copper II hydoxide + acetic acid
8. Hydrogen + Chlorine
9. Zinc hydroxide
10. Iron
+
à
à
à
Copper II Nitrate
11. Manganese sulfate
+
à
ammonium sulfide
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
à
12
Worksheet HH H CHEM
Name_______________
Equations- writing & balancing, Prediction of products
I. Priority #1-. Try to classify the reactions as either composition, decomposition, single or double
replacement, or combustion. Try to write the formulas of the product(s). Then balance each
equation.
__________1. Mg + O2 --->
__________2. Fe + O2 --->
__________3. H2O + SO2 --->
__________4. Fe + H2O --->
__________5. Al + Pb(NO3)2 --->
__________6. Ca + AgNO3 --->
__________7. K + H2O --->
__________8. LiCl + I2 --->
__________9. Ca(OH)2 + HCl --->
__________10. KOH + H3PO4 --->
__________11. Al(NO3)3 + H2SO4 --->
__________12. Na2SO3 + HCl --->
__________13. K2CO3 --->
__________14. NaOH --->
__________15. Mg(ClO3)2 --->
__________16. Na + Cl2 --->
__________17. Br2 + H2O + SO2 --->
__________18. CaO + H2O --->
__________19. Li2CO3 --->
__________20. Zn + HCl --->
__________21. KOH + H2SO4 --->
__________22. KClO3 --->
__________23. hydrochloric acid + aluminum oxide --->
__________24. ammonium hydroxide + nitric acid --->
__________25. silver nitrate + hydrogen sulfide --->
__________26. sodium hydroxide + phosphoric acid --->
__________27. mercury I nitrate + iron III chloride --->
__________28. C2H2 + oxygen --->
__________29. sulfur trioxide + water --->
__________30. tin + phosphoric acid --->
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
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__________31. mercuric hydroxide + potassium sulfate --->
__________32. siver nitrate + zinc chloride --->
__________33. oxygen + C7H16 --->
__________34. iron (III) + oxygen gas --->
__________35. potassium chlorate --->
__________36. iron + cupric chloride --->
__________37. magnesium + ferric chloride --->
__________38. copper + magnesium chloride --->
__________39. calcium + hydrochloric acid --->
__________40. cobalt + oxygen --->
__________41. nickel sulfate + lithium phosphate --->
__________42. sulfuric acid + sodium hydroxide --->
__________43. C8H18 + oxygen --->
__________44. ferrous oxide + aluminum --->
__________45. calcium carbonate + hydrochloric acid --->
__________46. barium hydroxide --->
__________47. zinc carbonate --->
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
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WORKSHEET II H Chem
NAME_____________
I. CLASSIFY EACH OF THE REACTIONS BELOW( COMP, DECOMP, ETC) , THEN PREDICT
THE PRODUCTS OF THE EQUATIONS BELOW. WRITE THE CORRECT FORMULAS AND
BALANCE EACH EQUATION.
1.
Potassium + Bromine à
à
2.
Iron II Chlorate
3.
Aluminum +
4.
C3H8 +
5.
Silver Nitrate +
Zinc Chlorideà
6.
Hydrogen
Sulfurà
7.
Nickel Carbonateà
8.
Iron II Sulfate +
Ammonium Sulfideà
9.
Copper II Bromide
+
Acetic acid à
10.
Barium Chloride
+
Sodium Sulfateà
11
Manganese Hydroxideà
12.
Calcium
+
Hydrochloric acidà
13.
Iron II Sulfide +
hydrochloric acidà
14.
Magnesium
+
Nitric Acidà
15.
Potassium
+ HOHà
16.
Lithium Iodide
+
17.
Silver
Sulfurà
18.
Sodium Chlorateà
19.
Zinc
20.
C6H12 +
21.
Lead Acetete +
Sulfuric Acidà
oxygenà
+
+
+
Chlorine gasà
Lead Acetateà
oxygenà
Hydrogen Sulfideà
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
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22.
Aluminum Bromide +
23.
Magnesium Carbonateà
24.
Barium Bromate
+
25
Aluminum
+
Oxygenà
26.
Sodium
+
HOHà
27.
Calcium Carbonate
28.
Hydrogen peroxideà
29.
Beryllium Hydroxide +
Nitric acidà
30.
Sodium Sulfite
Potassium Dichromateà
31.
C4H10 +
oxygenà
32.
Magnesium
+
33.
Iron III hydroxideà
34.
CH4
35.
Calcium Nitride
36.
Barium Phosphate
37.
Nickel oxide +
38.
Gold chlorideà
39.
cobalt Iodide +
+
+
+
Fluorineà
Potassium permanganateà
Hydrochloric acidà
oxygenà
oxygenà
+
Fluorineà
+
Sodium perchlorateà
Fluorineà
Sodium Sulfideà
40.** Zinc oxide
+
carbon dioxideà
41.** Zinc oxide
+
waterà
42.** Zinc chloride +
43.** water +
oxygenà
carbon dioxideà
44.** Sulfurous acid à
Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
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Mr Treuer Chem H Notes 2012-13 Unit 7 Equations
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