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WorksheetsChemistry Chapter 8: Balancing Equations Test Review
Total questions: 70
Worksheet time: 35mins
Knowledge about what products are produced in a chemical reaction is obtained by:
inspecting the chemical equation.
balancing the chemical equation.
laboratory analysis.
writing a word equation.
A chemical reaction has NOT occurred if the products have:
the same mass as the reactants.
less total bond energy than the reactants.
more total bond energy than the reactants.
the same chemical properties as the reactants.
Which observation does NOT indicate that a chemical reaction has occurred?
formation of a precipitate
production of a gas
evolution of heat and light
change in total mass of substances
A solid produced by a chemical reaction in solution that separates from the solution is called:
a. a precipitate.
b. a reactant.
c. a molecule.
d. the mass of the product.
After the correct formula for a reactant in an equation has been written, the:
subscripts are adjusted to balance the equation.
formula should not be changed.
same formula must appear as the product.
symbols in the formula must not appear on the product side of the equation.
In writing an equation that produces hydrogen gas, the correct representation of hydrogen gas is:
H.
H2.
OH.
2H.
What is the small whole number that appears in front of a formula in a chemical equation?
a. a subscript
b. a superscript
c. a ratio
d. a coefficient
To balance a chemical equation, it may be necessary to adjust the:
coefficients.
subscripts.
formulas of the products.
number of products.
According to the law of conservation of mass, the total mass of the reacting substances is:
always more than the total mass of the products.
always less than the total mass of the products.
sometimes more and sometimes less than the total mass of the products.
always equal to the total mass of the products.
A chemical equation is balanced when the:
coefficients of the reactants equal the coefficients of the products.
same number of each kind of atom appears in the reactants and in the products.
products and reactants are the same chemicals.
subscripts of the reactants equal the subscripts of the products.
Which word equation represents the reaction that produces water from hydrogen and oxygen?
Water is produced from hydrogen and oxygen.
Hydrogen plus oxygen yields water.
H2 + O2 → water.
Water can be separated into hydrogen and oxygen.
How would oxygen be represented in the formula equation for the reaction of methane and oxygen to yield carbon dioxide and water?
oxygen
O
O2
O3
Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen?
Carbon plus oxygen yields carbon dioxide.
C + O2 → CO2
CO2 → C + O2
2C + O2 → 2CO
For the formula equation 2Mg + O2 → 2MgO, the word equation would begin
Manganese plus oxygen ...
Magnesium plus oxygen ...
Molybdenum plus oxygen ...
Heat plus oxygen ...
In an equation, the symbol for a substance in water solution is followed by
(l)
(aq)
(g)
(s)
A chemical formula written over the arrow in a chemical equation signifies
a byproduct.
a catalyst for the reaction.
the formation of a gas.
an impurity.
When the equation Fe3O4 + Al → Al2O3 + Fe is correctly balanced, what is the coefficient of Fe?
3
4
6
9
Which coefficients correctly balance the formula equation NH4NO3(s) → N2(g) + H2O(l)?
2, 1, 2
1, 1, 2
2, 1, 1
2, 2, 2
Which coefficients correctly balance the formula equation CaO + H2O → Ca(OH)2?
2, 1, 2
1, 2, 1
1, 2, 3
1, 1, 1
After the first steps in writing an equation, the equation is balanced by
adjusting subscripts to the formula(s)
adjusting coefficients to the smallest whole-number ratio
changing the products formed
making the number of reactants equal to the number of products
The complete balanced equation for the reaction between zinc hydroxide and acetic acid is
ZnOH + CH3COOH → ZnCH3COO + H2O
Zn(OH)2 + CH3COOH → Zn + 2CO2 + 3H2O
Zn(OH)2 + 2CH3COOH → Zn(CH3COO)2 + 2H2O
Zn(OH)2 + 2CH3COOH → Zn(CH3COO)2 + H2 + O2
What is the balanced equation for the combustion of sulfur?
S(s) + O2(g) → SO(g)
S(s) + O2(g) → SO2(g)
2S(s) + 3O2(g) → SO3(s)
S(s) + 2O2(g) → SO42-(aq)
Which equation is NOT balanced?
2H2 + O2 → 2H2O
4H2 + 2O2 → 4H2O
H2 + H2 + O2 → H2O + H2O
2H2 + O2 → H2O
In what kind of reaction do two or more substances combine to form a new compound?
decomposition reaction
ionic reaction
double-replacement reaction
synthesis reaction
The equation AX → A + X is the general equation for a
synthesis reaction.
decomposition reaction.
combustion reaction.
single-replacement reaction.
In what kind of reaction does one element replace a similar element in a compound?
single-replacement reaction
double-replacement reaction
decomposition reaction
ionic reaction
The equation AX + BY → AY + BX is the general equation for a
synthesis reaction.
decomposition reaction.
single-replacement reaction.
double-replacement reaction.
The equation A + X → AX is the general equation for a(n)
combustion reaction.
ionic reaction.
synthesis reaction.
double-replacement reaction.
In what kind of reaction does a single compound produce two or more simpler substances?
decomposition reaction
synthesis reaction
single-replacement reaction
ionic reaction
The equation A + BX → AX + B is the general equation for a
double-replacement reaction.
decomposition reaction.
single-replacement reaction.
combustion reaction.
In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds?
synthesis reaction
double-replacement reaction
decomposition reaction
combustion reaction
The reaction 2Mg(s) + O2(g) → 2MgO(s) is a
synthesis reaction.
decomposition reaction.
single-replacement reaction.
double-replacement reaction.
The reaction Mg(s) + 2HCl(aq) → H2(g) + MgCl2(aq) is a
composition reaction
decomposition reaction
single-replacement reaction
double-replacement reaction
The reaction 2HgO(s) → 2Hg(l) + O2(g) is a(n)
single-replacement reaction.
synthesis reaction.
ionic reaction.
decomposition reaction.
The reaction Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) is a
double-replacement reaction.
synthesis reaction.
decomposition reaction.
combustion reaction.
The reaction 2KClO3(s) → 2KCl(s) + 3O2(g) is a(n)
synthesis reaction.
decomposition reaction.
combustion reaction.
ionic reaction.
The reaction Cl2(g) + 2KBr(aq) → 2KCl(aq) + Br2(l) is a(n)
synthesis reaction.
ionic reaction.
single-replacement reaction.
combustion reaction.
In one type of synthesis reaction, an element combines with oxygen to yield a(n)
acid.
hydroxide.
oxide.
metal.
The decomposition of a substance by an electric current is called
electrolysis.
conduction.
ionization.
transformation.
When heated, a metal carbonate decomposes into a metal oxide and
carbon.
carbon dioxide.
oxygen.
hydrogen.
Oxides of active metals, such as CaO, react with water to produce
metal carbonates.
metal hydrides.
acids.
metal hydroxides.
An active metal and a halogen react to form a(n)
salt.
hydroxide.
acid.
oxide.
When a binary compound decomposes, what is produced?
an oxide
an acid
a tertiary compound
two elements
Many metal hydroxides decompose when heated to yield metal oxides and
metal hydrides.
water.
carbon dioxide.
an acid.
When a metal chlorate is heated, it decomposes to yield a metal chloride and
a. a metal oxide.
b. a metal hydroxide.
c. hydrogen.
d. oxygen.
Some acids, such as carbonic acid, decompose to nonmetal oxides and
water.
a salt.
oxygen.
peroxide.
When heated, metallic chlorates decompose into
metallic oxides and chlorine.
metallic chlorides and oxygen.
a metal and a compound of chlorine and oxygen.
a metal, chlorine, and oxygen.
In the equation 2Al(s) + 3Fe(NO3)2(aq) → 3Fe(s) + 2Al(NO3)3(aq), iron has been replaced by
nitrate.
water.
aluminum.
nitrogen.
Group 1 metals react with water to produce metal hydroxides and
metal hydroxides.
hydrochloric acid.
oxygen.
hydrogen.
The replacement of bromine by chlorine in a salt is an example of a single-replacement reaction by
halogens.
sodium.
water.
electrolysis.
When a slightly soluble solid compound is produced in a double-replacement reaction,
gas bubbles off.
precipitate is formed.
combustion reaction takes place.
halogen is produced.
An insoluble gas that forms in a double-replacement reaction in aqueous solution
bubbles out of solution.
disassociates into ions.
forms a precipitate.
reacts with the water.
In a double-replacement reaction, hydrogen chloride and sodium hydroxide react to produce sodium chloride. Another product is
sodium hydride.
potassium chloride.
water.
hydrogen gas.
Active metals react with certain acids, such as hydrochloric acid, to yield a metal compound and
oxygen.
hydrogen.
chlorine.
sodium.
Some metals, such as iron, react with steam to produce hydrogen gas and a
metal hydroxide
metal hydride
metallic acid
metal oxide
When potassium reacts with water, one product formed is
hydrogen gas.
oxygen gas.
potassium oxide.
salt.
A precipitate forms in a double-replacement reaction when
hydrogen gas reacts with a metal.
positive ions combine with negative ions.
water boils out of the solution.
a gas escapes.
The reaction of calcium oxide (CaO) with water yields
calcium and oxygen gas.
calcium hydroxide.
calcium and a salt.
carbon dioxide and water.
Predict the product of the following reaction: MgO + CO2 →
MgCO3
Mg + CO3
MgC + O3
MgCO2 + O
Magnesium hydroxide decomposes to yield magnesium oxide and
hydrogen
oxygen
water
salt
The ability of an element to react is the element's:
valence
activity
stability
electronegativity
What is the name of a list of elements arranged according to the ease with which they undergo certain chemical reactions?
reactivity list
reaction sequence
activity series
periodic list
An element in the activity series can replace any element:
in the periodic table.
below it on the list.
above it on the list.
in its group.
What can be predicted by using an activity series?
whether a certain chemical reaction will occur
the amount of energy released by a chemical reaction
the electronegativity values of elements
the melting points of elements
The activity series of metals indicates the ease with which metal:
atoms gain neutrons.
nuclei fuse.
atoms form covalent bonds.
atoms lose electrons.
If metal X is lower than metal Y in the activity series, then metal X:
replaces ions of metal Y in a solution.
loses electrons more readily than does metal Y.
loses electrons less readily than does metal Y.
forms positive ions more readily than does metal Y.
Predict what happens when lead is added to nitric acid.
No reaction occurs.
Oxygen is released.
Lead oxide forms.
Hydrogen is released.
Predict what happens when nickel is added to a solution of potassium chloride.
No reaction occurs.
Nickel chloride forms.
Potassium nickel chloride forms.
Hydrochloric acid forms.
Which reaction does NOT occur?
2HF + Cl₂ → F₂ + 2HCl
2Na + ZnF₂ → 2NaF + Zn
Fe + CuCl₂ → FeCl₂ + Cu
2HCl + Mg → MgCl₂ + H₂
Which reaction can be predicted from the activity series?
2Cl → Cl₂
HCl + NaOH → NaCl + H₂O
2HCl + 2Na → 2NaCl + H₂
Cl₂ → 2Cl
