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WorksheetsChemistry Exam Review
Total questions: 109
Worksheet time: 55mins
A chemical equation is balanced when
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
A balanced chemical equation allows one to determine the
mole ratio of any two substances in the reaction
energy released in the reaction
electron configuration of all elements in the reaction
mechanism involved in the reaction
The coefficients in a chemical equation represent the
masses, in grams, of all reactants and products
relative numbers of moles of reactants and products
number of atoms in each compound in a reaction
number of valence electrons involved in the reaction
In the chemical reaction represented by the equation wA + xB -> yC + zD, a comparison of the number of moles of A to the number of moles of C would be a(n)
mass ratio
mole ratio
electron ratio
energy proportion
A chemical reaction involving substances A and B stops when B is completely used. B is the
excess reactant
limiting reactant
primary reactant
primary product
What is the ratio of the actual yield to the theoretical yield, multiplied by 100%?
mole ratio
percentage yield
Avogadro yield
excess yield
A balanced chemical equation allows one to determine the
mole ratio of any two substances in the reaction
energy released in the reaction
electron configuration of all elements in the reaction
mechanism involved in the reaction
Which reactant controls the amount of product obtained?
excess reactant
mole ratio
composition reactant
limiting reactant
In most chemical reactions, the product obtained is
equal to the theoretical yield
less than the theoretical yield
more then the theoretical yield
more then the percentage yield
The coefficients in a chemical equation represent the
masses, in grams, of all reactants and products
relative numbers of moles of reactants and products
numbers of atoms in each compound in a reaction
number of valence electrons involved in the reaction
If the percentage yield is equal to 100%, then
the actual yield is greater than the theoretical yield
the actual yield is equal to the theoretical yield
the actual yield is less than the theoretical yield
there was no limiting reactant
What is the measured amount of product obtained from a chemical reaction?
mole ratio
percentage yield
theoretical yield
actual yield
What is the maximum possible amount of product obtained in a chemical reaction?
theoretical yield
percentage yield
mole ratio
actual yield
To determine the limiting reactant in a chemical reaction, one must know the
available amount of one of the reactants
amount of product formed
available amount of each reactant
speed of the reaction
For an exothermic reaction, the products
are the same energy level as the reactants
have no energy
are at a lower energy level than the reactants
are at a higher energy level than the reactants
Delta E is positive for
an endothermic reaction
an exothermic reaction
an inhibited reaction
stable reaction
Delta H is always positive for a
spontaneous reaction
nonspontaneous reaction
exothermic reaction
endothermic reaction
Catalysts generally affect chemical reactions by
increasing the temperature of the system
increasing the surface area of the reactants
providing an alternate pathway with a lower activation energy
providing an alternate pathway with a higher activation energy
In what units are temperature measured?
degrees Celsius
kelvins
both a and b
none of the above
If the temperature of the reactants is lower,
the reaction rate is generally higher
the reaction rate is generally lower
the reaction rate is not affected
the rate-determining step is eliminated
Which of the following affects reaction rate?
the nature of reactants
surface area of reactants
temperature
all of the above
Activation energy is
the energy required to form the activated complex
the net energy required to turn reactants into products
the enthalpy of reaction
free energy
Raising the temperatures of reactants in a system
increases the average kinetic energy of the molecules
decreases the average kinetic energy of the molecules
decreases the rate of collision of molecules
has no effect on the avergae kinetic energy of molecules
The energy transferred between samples of matter because of a difference in their temperatures is called
heat
thermochemistry
chemical kinetics
temperature
Which of the following is the measure of the average kinetic energy of the particles in a sample of matter?
chemical kinetics
thermochemistry
reaction rate
temperature
In an endothermic reaction, the total energy at the beginning of the reaction is
greater than the total energy at the end of the reaction.
less than the total energy at the end of the reaction.
equal to total energy at the end of the reaction.
None of the above
The Greek letter delta stands for
heat stored in
mass of
rate of
change in
What units are used to measure energy as heat?
joules/mole or kilojoules/mole
kelvins or degrees Celsius
joules or kilojoules
non of the above
For an exothermic reaction, delta H is always
positive
negative
zero
small
The energy change, delta E, for a reaction is the energy difference between the
products and the intermediate
product and the reactant
product and the activated complex
reactant and the intermediate
The activation energy for a reaction is the energy difference between the
product and the intermediate
product and the reactant
reactant and the activated complex
reactant and the intermediate
The minimum energy required for a reaction to occur is called
energy of enthalpy
activation energy
free energy
kinetic energy
Which term has the same numerical value for the forward reaction as it has for the reverse reaction but with opposite sign?
delta E
activation energy
activation energy for the reverse reaction
delta T
What is the energy required to rais the temperature of 1 g of a substance by 1 degree Celsius or 1 K?
specific heat
heat energy
heat capacity
enthalpy of formation
In a potential energy graph, the activated complex is represented at the
left end of the curve
right end of the curve
bottom of the curve
top of the curve
If the surface area of reactants is larger,
the reaction rate is generally higher
the reaction rate is generally lower
the reaction rate is not affected
the rate-determining step is eliminated
If the concentration of a reactants is higher,
the reaction rate is generally higher
the reaction rate is generally lower
the reaction rate is not affected
the rate-determining step is eliminated
The particles in both gases and liquids
consist only of atoms
can change positions with other particles
can only vibrate in fixed positions
are packed closely together
The kinetic-molecular theory explains the behavior of
gases only
solids and liquids only
liquids and gases only
solids, liquids, and gases
In general, most substances are
least dense in the liquid state
more dense as gases than as solids
less dense as solids than as liquids
most dense in the solid state
Which term best describes the process by which particles escape from the surface of a nonboiling liquid and enter the gas state?
sublimation
evaporation
surface tension
aeration
Which of the following properties do solids share with liquids?
fluidity
definite shape
definite volume
slow rate of diffusion
Solids have a definite volume because
the particles do not have a tendency to change positions
the particles are far apart
they can be easily compressed
the energy of the particles is high
A solid forms when the average energy of a substance's particles
increases
decreases
decreases then increases
creates a random arrangement
Which of the following is a crystalline solid?
a plastic milk container
a quartz rock
a glass bottle
a three-dimensional glass cube
The difference between crystalline and amorphous solids is determined by
temperature changes
pressure when the substances are formed
amount of order in particle arrangement
strength of molecular forces
Which of the following is an amorphous solid
ice
diamond
graphite
glass
Which of these can happen due to decreasing the average energy of a liquid's particles?
vaporization
evaporation
a random arrangement
freezing
The density of a substance undergoes the greatest change when the substance changes from a
liquid to gas
liquid to solid
solid to liquid
a molecular solid to an ionic solid
The energy of the particles in a solid is
higher than the energy of the particles in a gas
high enough to allow the particles to interchange with other particles
higher than the energy of the particles in a liquid
lower than the energy of the particles in liquids and gases
The particles in a liquid are usually
closer together and lower in energy than those in a solid
farther apart and higher in energy than those in a gas
closer together and lower in energy than those in a gas
farther apart and lower in energy than those in a solid
The triple point of a substance is the temperature and pressure conditions at which
density is greatest
states of a substance coexist at equilibrium
equilibrium cannot occur
kinetic energy is at a minimum
What causes the high density of solids?
The particles are more massive than those in liquids.
The intermolecular forces between the particles are weak.
The particles are packed closely together.
The energy of the particles is very high.
Forces holding particles together are strongest in a
solid
liquid
gas
vapor
During boiling, the tempeature of a liquid
remains constant
increases
decreases
approaches water's boiling point
Above the critical temperature, a substance
does not have a vapor pressure
sublimes
cannot exist in the liquid state
is explosive
What happens to the volume of a gas during compression?
the volume increases
the volume decreases
the volume remains constant
it is impossible to tell because all gases are different
According to the kinetic-molecular theory, particles of matter
are in constant motion
have different shapes
have different colors
are always fluid
Which substance has the lowest density?
water in the gas state
water in the liquid state
Mercury in the liquid state
Mercury in the gas state
Particles within a solid
do not move
vibrate about fixed positions
move about freely
exchange positions easily
According to the kinetic-molecular theory, particles of matter are in motion in
gases only
gases and liquids only
solids, liquids, and gases
solids only
What is the process of a substance changing from a solid to a vapor without passing through the liquid phase?
condensation
evaporation
sublimation
vaporization
Standard pressure is exactly
760 atm
101 atm
1 atm
101.325 atm
To observe the effects of changing pressure on the volume of a gas, factors that must be kept constant are the gas's temperature and
quantity
elasticity
density
kinetic energy
When pressure, temperature, and volume are known, the ideal gas law can be used to calculate
molar amount
the ideal gas constant
rate of effusion
the chemical formula
If the temperature of a fixed quantity of gas decreases and the pressure remains unchanged,
its volume increases
its density increases
its volume is unchanged
its volume decreases
Why could the pressure of a sample of gas at a constant volume fall 75mm Hg?
The temperature decreased.
The container exploded.
The volume increased.
The temperature increased.
Knowing the mass an volume of a gas at STP allows one to calculate the
rate of diffusion of the gas
condensation point of the gas
molar mass of the gas
identity of the gas
Why does the air pressure inside the tires of a car increase when the car is driven?
The air particles collide with the tire after the car is in motion.
The air particles inside the tire increase their speed because their temperature rises.
Some of the air has leaked out.
The atmosphere compresses the tire.
What does the constant bombardment of gas molecules against the inside walls of a container produce?
temperature
density
pressure
diffusion
If the temperature of a fixed quantity and volume of gas changes, what also changes?
pressure
mass
density
formula
Standard temperature is exactly
100 degrees C
0 K
0 degrees C
273 degrees C
How many half-lives are required for 3/4 of the nuclei of one isotope in a sample to decay?
3/4
3/2
2
3
Gamma rays are
electrons
helium nuclei
electromagnetic waves
neutrons
To use radioactive dating for a substance, you must know the substance's
melting point
half-life
rate of weathering or erosion
enthalpy of reaction
What does the 4 in the alpha particle represent?
the mass number
the atomic number
the number of protons
the number of neutrons
Alpha particles are
electrons
helium nuclei
electromagnetic waves
neutrons
During radioactive decay, the nucleus disintegrates into
a lighter and more stable nucleus
a heavier and more stable nucleus
a lighter and less stable nucleus
a heavier and less stable nucleus
Which statement is true about half-lives?
different atoms of the same nuclide have different half-lives
each radioactive isotope has its own half-life
all radioactive nuclides of an element have the same half-life
all radioactive nuclides have the same half-life
Which statement about nuclear reactions is not true?
nuclear power plants use fission of uranium
in fission, nuclei are combined, and in fusion, nuclei are split
in fission, nuclei are split, and in fusion, nuclei are combined
heat and light in the sung are produced by fusion reactions
Which of the following is a fusion reaction?
uranium-235 absorbing a nuetron and splitting into xenon-140, strontium-95, and two neutrons
hydrochloric acid combining with sodium hydroxide to form NaCl and water.
carbon-14 decaying into nitrogen-14 and a beta particle
curium-246 combining with carbon-12 to form nobelium-254 and four neutrons
The energy released in a nuclear reaction comes from
electrons
bonds
positrons
the binding energy of the nucleus
Beta particles are
electrons
helium nuclei
electromagnetic waves
neutrons
What does the 218 in polonium-218 represent?
the mass number
the atomic number
the mass defect
the neutron number
In a nuclear reaction, unstable nuclei change their number of protons and neutrons,
give off large amounts of energy, and increase their stability
give off small amounts of energy, and increase their stability
give off large amounts of energy, and decrease their stability
give off small amounts of energy, and decrease their stability
Reactions that affect the nucleus of an atom are called
fusions
fissions
radioactive decays
nuclear reactions
Which of the following does not increase the rate of dissolving a solid in water?
raising the temperature of the water
stirring the solution
using larger pieces of solid
crushing the solid
In the expression "like dissolves like," the word like refers to similarity in molecular
mass
size
energy
polarity
IF the amount of a solute present in a solution at a given temperature is less than the maximum amount that can dissolve at the temperature, the solution is said to be
saturated
unsaturated
supersaturated
concentrated
A solute crystal is dropped into a solution containing dissolved solute. It falls to the bottom of the beaker and does not dissolve after vigorous stirring. What does this indicate about the solution?
it is probably unsaturated
it is probably super saturated
it is probably saturated
it is not at equilibrium
As temperature increases, solubility of solids in liquids
always increases
always decreases
usually increases
usually decreases
Which of the following is a homogeneous mixture of substances in a single phase?
a solution
a colloid
a compound
a suspension
Which of the following expresses concentration?
molality
molarity
moles of solute per liter of solution
all of the above
Sugar dissolved in water is an example of which solute-solvent combination?
gas-liquid
liquid-liquid
solid-liquid
liquid-solid
Carbon dioxide dissolved in water is an example of which solute-solvent combination
gas-liquid
liquid-gas
liquid-liquid
cannot be determined
A molar solution of calcium chloride contains
one mole of calcium chloride for every mole of solution
one mole of calcium chloride for every liter of solution
one liter of calcium chloride for every liter of solution
one liter of calcium chloride for every mole of solution
Which of the following will dissolve most rapidly?
sugar cubes in cold water
sugar cubes in hot water
powdered sugar in cold water
powdered sugar in hot water
An Arrhenius acid contains
hydrogen that does not ionize
hydrogen that ionizes to form hydrogen ions
oxygen that ionizes to form hydroxide ions
oxygen that ionizes to form oxygen ions
An acid ending with the suffix -ic produces an ion with the
suffix -ate
suffix -ite
prefix -hydro
suffix -ous
Acids taste
sweet
sour
bitter
salty
The traditional definition of acids is based on the observations of
Bronsted and Lowry
Lewis
Arrhenius
Mendeleev
Arrhenius theorized that an acid is a chemical compound that
increases the concentration of hydrogen ions when dissolved in water
increases the concentration of hydroxide ions when dissolved in water
decreases the concentration of hydrogen ions when dissolved in water
decreases the concentration of hydroxide ions when dissolved in water
Aqueous solutions of bases
contain only two different elements
carry electricity
have very high boiling points
cannot be prepared
Bases feel
rough
moist
slippery
dry
Arrhenius theorized that a base is a chemical compount that
increases the concentration of hydrogen ions when dissolved in water
increases the concentration of hydroxide ions when dissolved in water
decreases the concentration of hydrogen ions when dissolved in water
decreases the concentration of hydroxide ions when dissolved in water
Bases taste
soapy
sour
sweet
bitter
Acids generally release hydrogen has when they react with
nonmetals
semimetals
active metals
inactive metals
Aqueous solutions of acids
contain only two different elements
carry electricity
have very high boiling points
cannot be prepared
Acetic acid is found in
lemons
vinegar
sour milk
apples
