CHAPTERS 9&10 HEAT AND
THERMODYNAMICS EXAM QUESTIONS
WITH COMPLETE SOLUTIONS
give two examples of situations in which work results in an increase in a substance's
internal energy - ANSWER-hammering a nail
friction
splitting metal/wood
in addition of mechanical energy changes, what other type of energy changes occur
within a substance? when all energy changes are taken into account, what is found to
be true about the total energy of any system? - ANSWER-internal energy changes also
occur
total energy of any system is universally conserved
What is specific heat capacity? - ANSWER-the quantity of energy needed to raise the
temperature of 1kg of a substance by 1C at constant pressure and volume
Q=mCXT XT= Tf - Ti
What is calorimetry? what is the name of the device used to make such a
measurement? - ANSWER-an experimental procedure used to measure the energy
transferred from one substance to another as heat
calorimeter
what temperature serves as the melting point for ice? when energy is added to ice at
the melting point, what is found to happen to the temperature of the ice and water
mixture? - ANSWER-0C - when energy is added to ice at the melting point, the temp
remains at 0C until all of the ice has changed into water
what temperature serves as the boiling point for water? when energy is added to water
at the boiling point, what is found to happen to the temperature of the water and steam?
- ANSWER-100C - when energy is added to water at the boiling point, the temp remains
at 100C until all of the water has changed to steam
what is a phase change? - ANSWER-the physical change of a substance from one state
to another at constant temp and pressure
where does the energy go when a substance is undergoing a phase change? -
ANSWER-during the melting process, the energy goes to breaking the bonds of the well
ordered a solid crystal
vaporizing process, energy goes to separating the liquid bonds to create the weaker
bonding of gas
, what is latent heat? how is the energy transferred as heat during a phase change
calculated? - ANSWER-the energy per unit mass transferred in order to change a
substance from solid to/from liquid at constant temperature
Qf=mLf
which latent heat is involved with the melting process? The vaporization process? -
ANSWER-the energy per unit mass transferred in order to change a substance liquid
to/from vapor at constant temperature/pressure
Qv=mLv
why does a balloon inflate when placed over the mouth of a flask of water that is heated
to the boiling point - ANSWER-energy is added to the water as it is heated and changed
to steam. As volume of the steam expands, it pushes outward on the balloon, resulting
in inflation
How is work defined for a thermodynamic system? - ANSWER-the product of the
change in volume of gas and pressure applied on or by the gas
What is an isovolumetric process? - ANSWER-a thermodynamic process that takes
place at constant volume so that no work is done on the system.
In a bomb calorimeter, the energy released by the combustion reaction increases the
pressure and temperature of the gas. Since no volume change occurs, this energy is
transferred to or from the system as heat, allowing one to calculate the amount of
energy produced by the reaction.
What is an isothermal process? - ANSWER-A thermodynamic process that takes place
at constant temperature and in which the internal energy of a system remains
unchanged.
When the pressure around an inflated balloon decreases, the balloon does work on the
surrounding air and expands. During the expansion, energy is transferred into the
balloon as heat, keeping the temperature and internal energy of the balloon constant.
What is an adiabatic process? - ANSWER-A thermodynamic process during which work
is done on or by the system but no energy is transferred to or from the system as heat.
When a tank of compressed gas is used to fill a balloon, work is done by the gas as it
pushes the inner walls of the balloon outward, resulting in the balloon's inflation.
However, due the rapid nature of the inflation, little to no heat transfer occurs.
What does the first law of thermodynamics say about the relationship between internal
energy, heat, and work during a thermodynamic process? What does the first law of
thermodynamics imply about energy? - ANSWER-The change in a system's internal
energy = energy transferred to or form the system as heat - energy transfer to or from
the system as work. The first law is a statement of conservation of energy.
THERMODYNAMICS EXAM QUESTIONS
WITH COMPLETE SOLUTIONS
give two examples of situations in which work results in an increase in a substance's
internal energy - ANSWER-hammering a nail
friction
splitting metal/wood
in addition of mechanical energy changes, what other type of energy changes occur
within a substance? when all energy changes are taken into account, what is found to
be true about the total energy of any system? - ANSWER-internal energy changes also
occur
total energy of any system is universally conserved
What is specific heat capacity? - ANSWER-the quantity of energy needed to raise the
temperature of 1kg of a substance by 1C at constant pressure and volume
Q=mCXT XT= Tf - Ti
What is calorimetry? what is the name of the device used to make such a
measurement? - ANSWER-an experimental procedure used to measure the energy
transferred from one substance to another as heat
calorimeter
what temperature serves as the melting point for ice? when energy is added to ice at
the melting point, what is found to happen to the temperature of the ice and water
mixture? - ANSWER-0C - when energy is added to ice at the melting point, the temp
remains at 0C until all of the ice has changed into water
what temperature serves as the boiling point for water? when energy is added to water
at the boiling point, what is found to happen to the temperature of the water and steam?
- ANSWER-100C - when energy is added to water at the boiling point, the temp remains
at 100C until all of the water has changed to steam
what is a phase change? - ANSWER-the physical change of a substance from one state
to another at constant temp and pressure
where does the energy go when a substance is undergoing a phase change? -
ANSWER-during the melting process, the energy goes to breaking the bonds of the well
ordered a solid crystal
vaporizing process, energy goes to separating the liquid bonds to create the weaker
bonding of gas
, what is latent heat? how is the energy transferred as heat during a phase change
calculated? - ANSWER-the energy per unit mass transferred in order to change a
substance from solid to/from liquid at constant temperature
Qf=mLf
which latent heat is involved with the melting process? The vaporization process? -
ANSWER-the energy per unit mass transferred in order to change a substance liquid
to/from vapor at constant temperature/pressure
Qv=mLv
why does a balloon inflate when placed over the mouth of a flask of water that is heated
to the boiling point - ANSWER-energy is added to the water as it is heated and changed
to steam. As volume of the steam expands, it pushes outward on the balloon, resulting
in inflation
How is work defined for a thermodynamic system? - ANSWER-the product of the
change in volume of gas and pressure applied on or by the gas
What is an isovolumetric process? - ANSWER-a thermodynamic process that takes
place at constant volume so that no work is done on the system.
In a bomb calorimeter, the energy released by the combustion reaction increases the
pressure and temperature of the gas. Since no volume change occurs, this energy is
transferred to or from the system as heat, allowing one to calculate the amount of
energy produced by the reaction.
What is an isothermal process? - ANSWER-A thermodynamic process that takes place
at constant temperature and in which the internal energy of a system remains
unchanged.
When the pressure around an inflated balloon decreases, the balloon does work on the
surrounding air and expands. During the expansion, energy is transferred into the
balloon as heat, keeping the temperature and internal energy of the balloon constant.
What is an adiabatic process? - ANSWER-A thermodynamic process during which work
is done on or by the system but no energy is transferred to or from the system as heat.
When a tank of compressed gas is used to fill a balloon, work is done by the gas as it
pushes the inner walls of the balloon outward, resulting in the balloon's inflation.
However, due the rapid nature of the inflation, little to no heat transfer occurs.
What does the first law of thermodynamics say about the relationship between internal
energy, heat, and work during a thermodynamic process? What does the first law of
thermodynamics imply about energy? - ANSWER-The change in a system's internal
energy = energy transferred to or form the system as heat - energy transfer to or from
the system as work. The first law is a statement of conservation of energy.
