1. science
2. mathematics
3. algebra

Name: ______________________
EQUATION REVIEW
Fill-in:
In a chemical _________________________, the substance(s) entering the reaction
are(is) called _____________________ and the substance(s) that are(is) formed are(is) called
the ____________________. In a chemical reaction, atoms, molecules, or ions interact and
____________________ themselves to form the products. During this process, chemical
__________ are broken and ______________ bonds are formed. The reactants and products
may be in the solid, _____________, or _______________ state, or in
______________________ solution.
A chemical _____________________________, is a shorthand expression for a chemical
change or ______________________. A ____________________ equations states in words, in
equation form, the substance involved in a chemical _________________________. For example,
when mercury (II) oxide is heated, it ______________________ to form mercury and oxygen
gas. The word equation:
_______________________ and heat
mercury and ______________________
is bulky and cumbersome to use and does not give ______________________ information. So a
_____________________ equation is written first, showing correct formula and symbols and
states of matter:
_______________________
Hg(l) + ______________________.
According to the law of conservation of ____________, the equation must be balanced so
that there are equal number(s) of each kind of atom (_________________) on both sides of the
arrow. This is done by placing numbers in front of each formula (for a compound) or symbol (for an
element) that are called _______________________.
_______HgO(s)
_______Hg(l) + _________O2(g).
This equation is called a _____________________________ equation and shows formulas,
composition, and relative amounts of all substances involved. It does not show how much
_________ is needed to cause decomposition or anything about the __________________ of
reaction.
Many symbols other than those for the elements are used in an equation. A
____________________ is used to separate reactants and/or products. An _______________
means “________________” and separates products from reactants. An arrow pointing in each
direction,
means the reaction is _____________. A triangle above the arrow means _______
was added, and if there is a symbol of an element or formula for a compound above the arrow, it
means this substance is a __________. A solid can be shown with a _________or ________, gas
with a _______ or ________, and liquid with a ________. (aq) means the substance is an
____________ solution.
Reactions may be classified into types to assist in writing equations and to aid in
______________ products. There are six principal reactions types. The general form for the
first is A + B
AB, and this type is called ______________or ___________________
reactions. The general form of the second is AB
A + B, and this type is called ____________
or _________________ reactions. In a ___________________ reaction there are two general
forms, A + BC
C + BA, or A + BC
B + AC. The first example is showing A as a _________
replacing a ___________ ion. The second example is showing A as a ____________, replacing a
_____________ ion. The fourth type shown by general form, AB + CD
AD + CB is called a
________________________________ reaction and usually takes place in an ______________
solution. The fifth kind involves the ___________________ or _______________________
combustion of a carbon compound. The other reactant is ____________ gas and the products are
water and ___________________________ in complete combustion OR water and
__________________________ in incomplete. This kind just talked about also fits into a
category called oxidation-reduction (red-ox) reaction and even some reactions in the first five
categories. These reactions will be talked about later.
For reactions that take place in water another kind of equation can be written. A _______
ionic equation only shows those ions involved in the chemical reaction and eliminates ____________
ions who do not participate in the reaction and are said to just watch the reaction. These reactions
will have ______________ in aqueous solutions on the reactant side and compounds on the product
side as either a _____________, __________ or ___________.
PRACTICE PROBLEMS:
1.
Oxygen gas and potassium chloride are formed by heating potassium chlorate.
Write a………….
a.
Word Equation
b. Skeleton and then balanced equation
2. Water can be decomposed into its elements by using electricity when catalyzed by sulfuric acid.
Write a………….
a.
Word Equation
b. Skeleton and then balanced equation
3. Lithium metal reacts with water making hydrogen gas and sodium hydroxide.
Write a………….
a.
Word Equation
b. Skeleton and then balanced equation
DESCRIPTIVE CHEMISTRY:
Predict products, then balance. All products need to also have states of matter, ie.: (aq), (g), etc.
You do not need to write net ionic equations in this section, but may do so for practice to the right
of each equation.
1.
COMBINATION (various kinds)
a.
Metal + Oxygen
Mg(s) +
O2(g)
Al(s)
O2(g)
+
b. Nonmetal + Oxygen
makes water)
S(s) +
O2(g)
H2(g) +
O2(g)
Metal Oxide (Hint: use periodic table to predict product products formula)
Nonmetal Oxide (Hint: first reaction makes sulfur dioxide, the second
c.
Metal + Nonmetal
Na(s) +
Cl2(g)
Al(s)
Br2(g)
+
Salt (Hint: use periodic table to predict products formula)
d. Metal Oxide + Water
e.
Na2O(s) +
H2O(l)
CaO(s) +
H2O(l)
Metallic hydroxides (aka-a base or the hydroxide ion)
Nonmetal Oxide + Water
SO3(g) +
H2O(l)
CO2(g) +
H2O(l)
Oxy-acid
2. DECOMPOSITION (various kinds)
a.
Metal Oxide
Metal + Oxygen
MgO(s)
Al2O3(s)
b. Metallic Carbonate
Metal Oxide + Carbon Dioxide
CaCO3(s)
Al2(CO3)3(s)
c.
Misc.
KClO3
? + Oxygen gas
KCl
(s)
NaNO3
(s)
+
NaNO2
(s)
(s)
H2O2(aq)
3. SINGLE REPLACEMENT (various kinds)
a.
Metal* + Acid
Hydrogen Gas + Salt
Zn(s) +
HCl
Ca(s) +
H2SO4
(aq)
(aq)
*(K, Ca, Na, Mg, Al, Zn, Fe, Ni, Sn, Pb, all react with acids)
b. Metal** + Water
Cs(s) +
H 2O
(l)
Ca(s) +
H 2O
(l)
Hydrogen Gas + Metal Hydroxide
**(K, Ca, Na, (Li, Al, Zn, Fe) only with steam)
c.
Metal*** + Salt(aq)
Fe(s) +
CuSO4
Cu(s) +
AgNO3
Metal + Salt(aq) (Hint: both metal ions are +2 in charge)
(aq)
(aq)
***(H, Ca, Na, Mg, Al, Zn, Fe, Ni, Sn, Pb, Cu, Ag, Hg, Au)
d. Halogen + Halide Salt(aq)
F2(g) +
NaBr
Cl2(g) +
NaI
Activity Decreases
Halogen + Halide Salt(aq)
(aq)
(aq)
4. DOUBLE - REPLACEMENT (various kinds)
a.
Acid + Base
Water + Salt
H2SO4(aq) +
HCl(aq) +
Mg(OH)2
NaOH(aq)
b. Sol’n + Sol’n
CaCl2(aq) +
Sol’n + Precipitate (aka –an insoluble salt)
AgNO3(aq)
K2SO4(aq) +
c.
(aq)
BaCl2
(aq)
Formation of a Gas (Hint: first reaction makes a gas with a rotten egg smell and
second and third equation will produce three products)
HCl(aq) +
ZnS(s)
HCl(aq) +
CaCO3
HCl(aq) +
NaHCO3
(s)
(s)
Write a balanced equation for each statement. When appropriate you must also write a net ionic equation.
1.
Calcium metal slowly rust overtime when exposed to air.
2. Solid phosphorus (P4) is heat in a test tube with oxygen gas makes solid diphosphorus
pentaoxide.
3. Butane (C4H10) in a cigarette lighter undergoes complete combustion.
4. Nitric acid is neutralized with calcium hydroxide.
5. Aqueous solutions of mercurous nitrate and lithium chloride are mixed in a test tube.
6. A solution of silver nitrate is added to a nail made from iron in a test tube. The solution
goes from being colorless to a light yellow-green color.
7. Strontium chlorate is heated in a test tube. A wood splint that is glowing red relights when
placed in the mouth of the test tube.
8. Sodium metal is placed into a beaker of distilled water.
Classify the following reactions by placing on the blank the following symbols.
If no reaction takes place – NR, otherwise use: DR – double replacement; SR – single replacement;
C- combination (synthesis); D- decomposition (analysis). Then predict products and balance. All
products need to also have states of matter, ie.: (aq), (g), etc.
________ 1.
SO2(g) +
H2O(l)
________ 2.
H2SO4(aq ) +
________ 3.
KI(aq ) +
________ 4.
ZnCO3(s ) +
________ 5.
H2 (g ) +
________ 6.
(NH4)2S (aq ) +
________ 7.
MgCO3(s )
________ 8.
BaCl2(aq ) +
________ 9.
K(s ) +
________ 10.
Ag2O(s )
________ 11.
Cu(l ) +
________ 12.
K2O(s ) +
H2O(l)
________ 13.
KCl (aq ) +
NaNO3(aq)
________ 14.
Mg(ClO3)2(s)
________ 15.
Cl2(g ) +
NaF(aq)
________ 16.
Fe(s ) +
O2(g)
________ 17.
Mg(s) +
NaOH(aq)
Br2(s)
HCl(aq)
Cl2(g)
HI(aq)
Na2SO4(aq)
H2O(l)
HCl(l)
Zn(NO3)2(aq)
________ 18.
ZnCl2(aq ) +
________ 19.
F2(s ) +
________ 20.
CaO(s ) +
NaOH(aq)
NaI(aq)
H2O(l)
AP Chemistry Free Response #4
Directions
 In the box follow these directions (5 points extra credit for each)
Write the formulas to show the reactants and products for ALL of the laboratory situations described
below.
In all cases a reaction occurs.
Assume that solutions are aqueous unless otherwise indicated.
Represent substances in solution as ions if the substances are extensively ionized.
Omit formulas for any ions or molecules that are unchanged by the reaction.
You need to balance the equations.
1.
A solution of potassium hydroxide is added to a solution of copper (II) sulfate.
a.
2.
Identify the spectator ions
Liquid chlorine is shaken with a sodium iodide solution.
a. Which substance is undergoing reduction?
3.
Aluminum metal is added to a solution of hydrochloric acid.
a. What subatomic particle is being exchanged between the reactants and how many