GENERAL CHEMISTRY FINAL EXAM
QUESTIONS AND ANSWERS
definition of thermochemistry - Correct Answers -branch of thermodynamics that deals
with the evolution of absorption of energy as heat in chemical processes
what is an everyday example of heat evolving from a chemical reaction - Correct
Answers -burning of petroleum for energy
what does the reaction system include? - Correct Answers -all the chemicals involved in
the reaction
what does the surrounding consist of? - Correct Answers -everything else, such as
containers and the atmosphere
what are the two ways in which energy can be transferred between a reaction system
and its surroundings? - Correct Answers -either as work or as heat
when does the system gain energy as work? - Correct Answers -when the work is
positive
when does the system lose energy as work? - Correct Answers -when the work is
negative
conversion of 1 L*atm to J - Correct Answers -1 L*atm = 101.325 J
what is it called when the system transfers energy as heat to the suroundings - Correct
Answers -exothermic
what is the value of q and U in an exothermic reaction - Correct Answers -negative
what is it called when the system gains energy as heat from the surroundings - Correct
Answers -endothermic
what is the value of q and U in an endothermic reaction? - Correct Answers -positive
what does U stand for? - Correct Answers -the energy of a system
what is the first law of thermodynamics? - Correct Answers -equivalent to the law of
conservation of energy
, state functions - Correct Answers -functions that depend only on the state of a system,
not on how that state is achieved
what is the value of w when system is compressed? - Correct Answers -positive
what is the value of w when system is expanded - Correct Answers -negative
how do you calculate the energy released as heat - Correct Answers -1. balance
equation and find changeH
2. finding limiting reactant
3. multiply moles of limiting reactant by changeH/mole
how do you calculate change in Urxn when given equation and change Hrexn - Correct
Answers -1. Fine change in moles of gas (coefficients)
2. multiply change by RT
3.subtract from change Hrxn
what is the value of Change Hrxn when adding two equations - Correct Answers -add
the two change Hrxn
how to calculate changeHf - Correct Answers -Use hess's law
how to find change Hrxn using bond energies - Correct Answers -(energy required to
break bonds in reatants)-(energy evolved as heat upon formation of bonds in product)
how to calculate change Hrxn using change Hf - Correct Answers -products change Hf -
reactants change Hf
how to calculate molar bond enthalpy using change Hf - Correct Answers -1. calculate
change Hrxn using change Hf
2. divide by number of bonds
definition of heat capacity - Correct Answers -energy in the form of heat required to
raise the temperature of the sample by one degree
what does qp=? - Correct Answers -change of H
how to calculate heat capacity? - Correct Answers -heat energy/changeT
how to calculate molar heat capacity - Correct Answers -heat capacity/moles
how to calculate heat required to raise the temperature using molar heat capacity -
Correct Answers -=(moles)(molar heat capacity)(changeT)
definition of specific heat - Correct Answers -heat capacity per gram of substance
QUESTIONS AND ANSWERS
definition of thermochemistry - Correct Answers -branch of thermodynamics that deals
with the evolution of absorption of energy as heat in chemical processes
what is an everyday example of heat evolving from a chemical reaction - Correct
Answers -burning of petroleum for energy
what does the reaction system include? - Correct Answers -all the chemicals involved in
the reaction
what does the surrounding consist of? - Correct Answers -everything else, such as
containers and the atmosphere
what are the two ways in which energy can be transferred between a reaction system
and its surroundings? - Correct Answers -either as work or as heat
when does the system gain energy as work? - Correct Answers -when the work is
positive
when does the system lose energy as work? - Correct Answers -when the work is
negative
conversion of 1 L*atm to J - Correct Answers -1 L*atm = 101.325 J
what is it called when the system transfers energy as heat to the suroundings - Correct
Answers -exothermic
what is the value of q and U in an exothermic reaction - Correct Answers -negative
what is it called when the system gains energy as heat from the surroundings - Correct
Answers -endothermic
what is the value of q and U in an endothermic reaction? - Correct Answers -positive
what does U stand for? - Correct Answers -the energy of a system
what is the first law of thermodynamics? - Correct Answers -equivalent to the law of
conservation of energy
, state functions - Correct Answers -functions that depend only on the state of a system,
not on how that state is achieved
what is the value of w when system is compressed? - Correct Answers -positive
what is the value of w when system is expanded - Correct Answers -negative
how do you calculate the energy released as heat - Correct Answers -1. balance
equation and find changeH
2. finding limiting reactant
3. multiply moles of limiting reactant by changeH/mole
how do you calculate change in Urxn when given equation and change Hrexn - Correct
Answers -1. Fine change in moles of gas (coefficients)
2. multiply change by RT
3.subtract from change Hrxn
what is the value of Change Hrxn when adding two equations - Correct Answers -add
the two change Hrxn
how to calculate changeHf - Correct Answers -Use hess's law
how to find change Hrxn using bond energies - Correct Answers -(energy required to
break bonds in reatants)-(energy evolved as heat upon formation of bonds in product)
how to calculate change Hrxn using change Hf - Correct Answers -products change Hf -
reactants change Hf
how to calculate molar bond enthalpy using change Hf - Correct Answers -1. calculate
change Hrxn using change Hf
2. divide by number of bonds
definition of heat capacity - Correct Answers -energy in the form of heat required to
raise the temperature of the sample by one degree
what does qp=? - Correct Answers -change of H
how to calculate heat capacity? - Correct Answers -heat energy/changeT
how to calculate molar heat capacity - Correct Answers -heat capacity/moles
how to calculate heat required to raise the temperature using molar heat capacity -
Correct Answers -=(moles)(molar heat capacity)(changeT)
definition of specific heat - Correct Answers -heat capacity per gram of substance
