Thermochemistry and Kinetics - AP Chemistry
Card 0 of 2013
The second law of thermodynamics states which of the following is true regarding an isolated system?
The second law of thermodynamics states which of the following is true regarding an isolated system?
The entropy cannot decrease in an isolated system because the energy can only be degraded. Since the system is isolated, no higher-grade energy—or any energy at all—is being introduced into the system. As a result, the entropy cannot decrease. The other answer choices relate to the other laws of thermodynamics.
The entropy cannot decrease in an isolated system because the energy can only be degraded. Since the system is isolated, no higher-grade energy—or any energy at all—is being introduced into the system. As a result, the entropy cannot decrease. The other answer choices relate to the other laws of thermodynamics.
Compare your answer with the correct one above
Which of the following statements is true of standard states?
Which of the following statements is true of standard states?
Standard states are defined as a specific set of conditions, such as when a gas is at 
, 
concentration, and 
.
Standard enthalpy of formation, the energy required for form 1 mole of a compound from its constituent elements, occurs when elements are in their standard states.
Standard states are defined as a specific set of conditions, such as when a gas is at
Standard enthalpy of formation, the energy required for form 1 mole of a compound from its constituent elements, occurs when elements are in their standard states.
Compare your answer with the correct one above
How much heat is required to raise the temperature of 
of water from 
to 
? (Specific heat capacity of water is 
)
How much heat is required to raise the temperature of
is positive because heat flows into the system to raise the temperature of the water.
Compare your answer with the correct one above
How much heat is required to raise the temperature of 
of water from 
to 
? Specific heat capacity of water is 
How much heat is required to raise the temperature of
Compare your answer with the correct one above
Calculating heat
How much heat is absorbed by a copper penny as it warms from 
to 
assuming the penny is pure copper with a mass of 
? 
of copper is 
.
Calculating heat
How much heat is absorbed by a copper penny as it warms from
Use the equation that relates heat, mass, specific heat, and change in temperature:
Use the equation that relates heat, mass, specific heat, and change in temperature:
Compare your answer with the correct one above
"In a natural thermodynamic process, the sum of the entropies of the interacting systems increases." Which law of thermodynamics does this statement refer to?
"In a natural thermodynamic process, the sum of the entropies of the interacting systems increases." Which law of thermodynamics does this statement refer to?
There are four main laws of thermodynamics, which describe how temperature, energy, and entropy behave under various circumstances. The zeroth law of thermodynamics helps to define temperature; it states that if two systems are each in thermal equilibrium with a third system, they must be in thermal equilibrium with each other. The first law of thermodynamics negates the possibility of perpetual motion; it states that when energy passes into or out of a system, the system's internal energy changes in accord with the law of conservation of energy. The second law of thermodynamics also negates the possibility of perpetual motion; it states that in a natural thermodynamic process, the sum of the entropies of the interacting systems increases. Lastly, the third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature nears absolute zero.
There are four main laws of thermodynamics, which describe how temperature, energy, and entropy behave under various circumstances. The zeroth law of thermodynamics helps to define temperature; it states that if two systems are each in thermal equilibrium with a third system, they must be in thermal equilibrium with each other. The first law of thermodynamics negates the possibility of perpetual motion; it states that when energy passes into or out of a system, the system's internal energy changes in accord with the law of conservation of energy. The second law of thermodynamics also negates the possibility of perpetual motion; it states that in a natural thermodynamic process, the sum of the entropies of the interacting systems increases. Lastly, the third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature nears absolute zero.
Compare your answer with the correct one above
Which of the following is the correct molar specific heat of water used when making calculations involving a calorimeter?
Which of the following is the correct molar specific heat of water used when making calculations involving a calorimeter?
4.184 J/gK is the cited value for the specific heat of water and should be memorized. This is used during calorimeter calculations, specifically when using the equation q= mc delta(T).
4.184 J/gK is the cited value for the specific heat of water and should be memorized. This is used during calorimeter calculations, specifically when using the equation q= mc delta(T).
Compare your answer with the correct one above
In which instance would a bomb calorimeter be more useful than a coffee-cup calorimeter?
In which instance would a bomb calorimeter be more useful than a coffee-cup calorimeter?
Bomb calorimeters are most useful when dealing with a gas, because they can operate well at high pressures. Coffee-cup calorimeters are not useful when water begins to boil, producing vapor.
Bomb calorimeters are most useful when dealing with a gas, because they can operate well at high pressures. Coffee-cup calorimeters are not useful when water begins to boil, producing vapor.
Compare your answer with the correct one above
__________ the activation energy of a reaction will __________ the amount of products produced.
__________ the activation energy of a reaction will __________ the amount of products produced.
This question is asking about the relationship between activation energy of a reaction (kinetics) and the amount of products produced (equilibrium). Remember that altering the speed of a reaction (kinetics) does not change the equilibrium of the reaction. Increasing or decreasing activation energy (which alters the speed of reaction) will simply allow for the reaction to proceed slower or faster, respectively. It will not change the amount of products produced at the end.
This question is asking about the relationship between activation energy of a reaction (kinetics) and the amount of products produced (equilibrium). Remember that altering the speed of a reaction (kinetics) does not change the equilibrium of the reaction. Increasing or decreasing activation energy (which alters the speed of reaction) will simply allow for the reaction to proceed slower or faster, respectively. It will not change the amount of products produced at the end.
Compare your answer with the correct one above
Which of the following is not an assumption of the kinetic molecular theory of gases?
Which of the following is not an assumption of the kinetic molecular theory of gases?
The kinetic molecular theory of gases states that the average kinetic energy of gas particles is proportional to temperature, and it is the same for all gases at a given temperature. This is the opposite of what is stated in the answer choice.
The kinetic molecular theory of gases states that the average kinetic energy of gas particles is proportional to temperature, and it is the same for all gases at a given temperature. This is the opposite of what is stated in the answer choice.
Compare your answer with the correct one above
Which of the following is not true of the transition state?
Which of the following is not true of the transition state?
The transition state is the energy barrier in a reaction—energy is needed to reach this state. Once it is acheived, however, it can either revert back to reactants or dissociate into products without any added energy.
The transition state is the energy barrier in a reaction—energy is needed to reach this state. Once it is acheived, however, it can either revert back to reactants or dissociate into products without any added energy.
Compare your answer with the correct one above
Which of the following does not affect a forward reaction rate?
Which of the following does not affect a forward reaction rate?
Product concentration would not affect a forward reaction rate, since that is what is being formed. Catalysts specifically speed up reaction rates, as does temperature. Medium can also affect reaction rate because some molecules are more likely to react with each other in certain environments.
Product concentration would not affect a forward reaction rate, since that is what is being formed. Catalysts specifically speed up reaction rates, as does temperature. Medium can also affect reaction rate because some molecules are more likely to react with each other in certain environments.
Compare your answer with the correct one above
Which of the following is true of catalysts?
Which of the following is true of catalysts?
Catalysts are substances that increase reaction rates without being consumed in the reaction. They decrease the activation energy needed, and they do not always need to be in the same phase as the reactants. In heterogeneous catalysis, the catalyst is in a different phase than the reactants. Equilibrium concentrations of both reactants and products are unchanged by the addition of a catalyst.
Catalysts are substances that increase reaction rates without being consumed in the reaction. They decrease the activation energy needed, and they do not always need to be in the same phase as the reactants. In heterogeneous catalysis, the catalyst is in a different phase than the reactants. Equilibrium concentrations of both reactants and products are unchanged by the addition of a catalyst.
Compare your answer with the correct one above
Which of the following is not true of catalysts?
Which of the following is not true of catalysts?
All of the choices are true, except that catalysts can be in distinct phases than the reactants. These are known as heterogenous catalysts.
All of the choices are true, except that catalysts can be in distinct phases than the reactants. These are known as heterogenous catalysts.
Compare your answer with the correct one above
How does adding a catalyst affect a reaction?
How does adding a catalyst affect a reaction?
A catalyst is a substance that increases the rate of a reaction, typically by lowering the activation energy required to initiate a reaction. The catalyst does not affect the equilibrium of a reaction, and is not consumed during the reaction.
A catalyst is a substance that increases the rate of a reaction, typically by lowering the activation energy required to initiate a reaction. The catalyst does not affect the equilibrium of a reaction, and is not consumed during the reaction.
Compare your answer with the correct one above
A catalyst increases the rate of a reaction by which of the following mechanisms?
A catalyst increases the rate of a reaction by which of the following mechanisms?
A catalyst has no effect on the relative stability of the reactants or products, nor does it effect the temperature of a reaction.
Instead, catalysts lower the energy of transition states, increasing their stability, to lower the overall activation energy of the reaction. When the reaction requires less energy, it proceeds at a faster rate.
A catalyst has no effect on the relative stability of the reactants or products, nor does it effect the temperature of a reaction.
Instead, catalysts lower the energy of transition states, increasing their stability, to lower the overall activation energy of the reaction. When the reaction requires less energy, it proceeds at a faster rate.
Compare your answer with the correct one above
Name the catalyst in each reaction.
I. 
II. 
Name the catalyst in each reaction.
I.
II.
A catalyst will not be consumed during a reaction, so the catalyst will be whichever chemical is found both on the reactant side of the equation and on the product side.
For equation 1 that is compound Z; for equation 2 that is compound A.
A catalyst will not be consumed during a reaction, so the catalyst will be whichever chemical is found both on the reactant side of the equation and on the product side.
For equation 1 that is compound Z; for equation 2 that is compound A.
Compare your answer with the correct one above
What is the function of a catalyst in a chemical reaction?
What is the function of a catalyst in a chemical reaction?
Catalysts increase the reaction rate without being consumed during the reaction. They don't cause the reaction to make more product, but since the catalyst won't be used up in the reaction.
Catalysts increase the reaction rate without being consumed during the reaction. They don't cause the reaction to make more product, but since the catalyst won't be used up in the reaction.
Compare your answer with the correct one above
Enzymes are very physiologically and industrially important molecules. From cheese-making to the metabolism of toxins, we need enzymes for life and society as we know it.
Which of the following is not true of enzymes?
Enzymes are very physiologically and industrially important molecules. From cheese-making to the metabolism of toxins, we need enzymes for life and society as we know it.
Which of the following is not true of enzymes?
Enzymes function by forming complexes with their substrates at active sites. This interaction is often thought of as a lock and key mechanism, in the sense that the active site is shaped to fit a substrate.
Enzymes are biological catalysts and therefore they work to lower the energy barrier or activation energy that prevents a reaction from proceeding to equilibrium. In other words: enzymes and catalysts in general make a reaction reach equilibrium faster.
Therefore enzymes do not change the equilibrium product concentration, just the time it takes to get to equilibrium.
Enzymes function by forming complexes with their substrates at active sites. This interaction is often thought of as a lock and key mechanism, in the sense that the active site is shaped to fit a substrate.
Enzymes are biological catalysts and therefore they work to lower the energy barrier or activation energy that prevents a reaction from proceeding to equilibrium. In other words: enzymes and catalysts in general make a reaction reach equilibrium faster.
Therefore enzymes do not change the equilibrium product concentration, just the time it takes to get to equilibrium.
Compare your answer with the correct one above
Which of the following statements regarding catalysts is true?
Which of the following statements regarding catalysts is true?
Note that when catalyst decreases the activation energy (Ea), 
will not be affected. The step in a reaction with the largest activation energy usually is the slow step, which catalysts facilitate. Catalysts do not affect the thermodynamic quantities 
. Since catalysts are not consumed in the reaction, they do not appear in the net equation of the reaction.
Note that when catalyst decreases the activation energy (Ea),
Compare your answer with the correct one above