Chem Semester Test
What unknown quantity can be calculated after performing a titration?
concentration
The reaction represented by the equation 2KClO3(s) -> 2KCl(s) + 3O2 is a(n)
decomposition reaction
The reaction represented by the equation Pb(NO3)2(aq) + 2KI(aq) -> PbI2(s) + 2KNO3(aq) is a
double-displacement reaction
For a chemical reaction, percentage yield represents the
efficiency
Actual yield must be determined by
experiments
Active metals react with certain acids, such as hydrochloric acid, to yield a metal compound and
hydrogen
Dyes with pH-sensitive colors are used as...
indicators
A water solution whose pH is 4...
is always acidic
A water solution whose pH is 10...
is always basic
If [H3O+] of a solution is less than [OH-], the solution...
is always basic
A water solution whose pH is 7...
is always neutral
In an acid-base titration, the primary standard...
is either a highly pure acid or a highly pure base
In the figure above, the pH at the equivalence point...
is less than 7.0
In most chemical reactions, the amount of product obtained is
less than the theoretical yield
The actual yield of a chemical reaction is generally
less than the theoretical yield
The participation of reactants in a chemical reaction is restricted by the
limiting reactant
Which expression can be used to solve a mass-to-mole conversion for the equation 2HCl -> H2 + Cl2
mass HCL X 1 mol HCL/molar mass HCL X 1 mol Cl2/2 mol HCl
Oxides of active metals, such as CaO, react with water to produce
metal hydroxides
When heated, metallic chlorates decompose into
metallic chlorides and oxygen
A balanced chemical equation allows one to determine the
mole ratio of any two substances in the reaction
An acid-base titration involves a...
neutralization reaction
Predict what happens when zinc is added to water
no reaction occurs
An acid-base titration is carried out by monitoring...
pH
which of the following mathematical expressions correctly states the relationship among percentage yield, actual yield, and theoretical yield
percentage yield = actual yield/theoretical yield X 100 AND theoretical yield = actual yield/percentage yield X100
When a slightly soluble solid compound is produced in a double-displacement reaction, a
precipitate is formed
The coefficients in a chemical equation represent the
relative numbers of moles of reactants and products
An active metal and a halogen react to form a(n)
salt
A chemical equation is balanced when the
same number of each kind of atom appears in the reactants and in the products
The reaction represented by the equation Cl2(g) + 2KBr(aq) -> 2KCl(aq) + Br2(l) is a(n)
single-displacement reaction
How would you classify nitric acid (HNO3) in the reaction represented by the equation below? HNO3 (l) + H2O (l) = H3O+ (aq) = NO3- (aq)
strong acid
The reaction represented by the equation 2Ca(s) + O2(g) -> 2CaO(s) is a
synthesis reaction
When you conduct an acid-base titration...
the equivalence point must be reached
Knowing the mole ratio of a reactant and product in a chemical reaction would allow you to determine
the mass of the product produced from a known mass of reactant
Indicators are classified into three types according to...
the pH at which they change color
Fewer steps are required to solve stoichiometry problems when
the reactant is given in moles and the product is sought in moles
If a chemist calculates the maximum amount of product that could be obtained in a chemical reaction, he or she is calculating the
theoretical yield
The limiting reactant of a reaction can be used to calculate the
theoretical yield
What process measure the amount of a solution of known-concentration required to react with a measured amount of a solution of unknown concentration?
titration
The pH range over which an indicator changes color is its...
transition interval
When a binary compound decomposes, what is produced?
two elements
A pH meter measures the pH of a solution by measuring the...
voltage difference between two electrodes in the meter's probe
Which quantity is directly measured in a titration?
volume
Many metal hydroxides decompose when heated to yield metal oxides and
water
Pure water contains...
water molecules, hydronium ions, and hydroxide ions
In an equation, the symbol for a substance in water solution is followed by
(aq)
Which expression represents the pH of a solution?
-log[H3O+]
The pH scale in general use ranges from...
0-14
Calculate the molarity of a Ba(OH)2 solution if 1900 mL is completely titrated by 261 mL of 0.505 M HNO3.
0.0347 M
What is the molarity of an H2SO4 solution if 49.0 mL is completely titrated by 68.4 mL of an NaOH solution whose concentration is 0.333 M?
0.232 M
What is the pH of a solution whose hydronium ion concentration is 5.03 x 10^-1 M?
0.2984
What is the molarity of an HCl solution if 50.0 mL is neutralized in a titration by 40.0 mL of 0.400 M NaOH?
0.320 M
What is the molarity of an NaOH solution if 4.37 mL is titrated by 11.1 mL of 0.0904 M HNO3?
0.320 M
What is the molarity of an HCl solution if 125 mL is neutralized in a titration by 76.0 mL of 1.22 M KOH?
0.742 M
What is the [OH-] in a 0.1 M HCl solution?
1 10^-13 M
Which of the following expressions is not a legitimate conversion factor
1 g C/6.022 X 10^23 atoms C
The pH of a solution is 9.0. What is its H3O+ concentration?
1 x 10^-9 M
The pH of a solution is 10.00. What is its OH- concentration?
1.0 x 10^-4 M
The [OH-] of an aqueous solution is 6.4 x 10^-5 M. What is the [H3O+]?
1.6 x 10^-10 M
What is the product of H3O+ ion and OH- ion concentrations in water?
10^-14
What is the concentration of H3O+ ions in pure water?
10^-7 M
What is the pH of a 0.001 62 M NaOH solution?
11.210
What is the pH of a 0.027 M KOH solution?
12.43
In the titration of a solution of Sr(OH)2 with HCl, the mole ratio of hydroxide ions to hydronium ions is...
1:2?
For the equation P4(s) + 5O2(g) -> P4O10(s), if 3 mol of phosphorus react with 10 mol of oxygen, the theoretical yield of phosphorus(V) oxide will be
2 mol
Which coefficients correctly balance the formula equation Mg + O2 -> MgO
2,1,2
If 72.1 mL of 0.543 M H2SO4 completely titrates 39.0 mL of KOH solution, what is the molarity of the KOH solution?
2.01 M
What is the OH- concentration of a solution whose pH is 12.40?
2.5 x 10-2 M
If [H3O+] = 1.7 x 10^-3, what is the pH of the solution?
2.77
What is the balanced equation when aluminum reacts with copper(II) sulfate
2Al + 3CuSO4 -> Al2(SO4)3 + 3Cu
In the equation Al2(SO4)3 + 3Ca(OH)2 -> 3CaSO4 + 2Al(OH)3, the mole ratio of calcium hydroxide to aluminum hydroxide is
3:2
What is the pH of a 10^-4 M HCl solution?
4
In the equation 2Al2O3 -> 4Al + 3O2, what is the mole ratio of aluminum to oxygen
4:3
In the figure above, the volume of titration standard necessary to reach the equivalence point is...
50 mL
What is the mole ratio of H2O to H3PO4 in the following chemical equation? P4O10 + 6H2O -> 4H3PO4
6 to 4
What is the hydronium ion concentration of a solution whose pH is 4.12?
7.6 x 10^-5 M
What is the pH of a 10^-5 M KOH solution?
9
When the equation Fe3O4 + Al --> Al2O3 + Fe is correctly balanced, what is the coefficient of Fe?
9
In the reaction represented by the equation A + B -> C + D, if there is more reactant B than is required to completely react with all of A, then
A is the limiting reactant
Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen
C + O2 -> CO2
Which is an example of a weak acid?
H3PO4
Predict the product of the reaction represented by the following equation: MgO + CO2 ->
MgCO3
How would oxygen be represented in the formula equation for the reaction of methane and oxygen to yield carbon dioxide and water?
O2
What is the balanced equation for the combustion of sulfur
S(s) + O2(g) -> SO2(g)
A standard solution always contains...
a known concentration of solute
When a solid produced by a chemical reaction separates from the solution it is called
a precipitate
Which observation indicates that a chemical reaction has occurred
a precipitate
Which of the properties listed below is NOT characteristic of an acid?
a slippery feel
The figure above shows an example of the titration of...
a strong acid with a weak base
How would you classify KOH in the equation below? KOH (aq) = K+ (aq) + OH- (aq)
a strong base
How would you classify CH3COOH in the equation below? CH3COOH (aq) + H2O (l) = H3O+ (aq) + CH3CO- (aq)
a weak acid
According to the law of conservation of mass, the total mass of the reacting substances is
always equal to the total mass of the products
An acid-base titration determines the volumes of two solutions that...
are chemically equivalent
In an acid-base titration, equivalent quantities of hydronium ions and hydroxide ions are present...
at the midpoint
In an acid-base titration...
base is added to acid or acid is added to base
An element in the activity series can replace any element
below it on the list
An insoluble gas that forms in a double-displacement reaction in aqueous solution
bubbles out of solution
Predict what happens when calcium metal is added to a solution of magnesium chloride
calcium chloride forms
The reaction of calcium oxide, CaO, with water yields
calcium hydroxide
To determine the limiting reactant in a chemical reaction involving known masses of the two reactants, which of the following would be most useful
calculating the mass of a single product formed from each reactant
When heated, a metal carbonate decomposes into a metal oxide and
carbon dioxide
