General Chemistry Final Exam with
Complete Solutions
definition of thermochemistry - correct answer-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
answer-burning of petroleum for energy
what does the reaction system include? - correct answer-all the chemicals involved in
the reaction
what does the surrounding consist of? - correct answer-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 answer-either as work or as heat
when does the system gain energy as work? - correct answer-when the work is positive
when does the system lose energy as work? - correct answer-when the work is negative
conversion of 1 L*atm to J - correct answer-1 L*atm = 101.325 J
what is it called when the system transfers energy as heat to the suroundings - correct
answer-exothermic
what is the value of q and U in an exothermic reaction - correct answer-negative
what is it called when the system gains energy as heat from the surroundings - correct
answer-endothermic
what is the value of q and U in an endothermic reaction? - correct answer-positive
what does U stand for? - correct answer-the energy of a system
what is the first law of thermodynamics? - correct answer-equivalent to the law of
conservation of energy
state functions - correct answer-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 answer-positive
what is the value of w when system is expanded - correct answer-negative
how do you calculate the energy released as heat - correct answer-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
answer-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 answer-add the
two change Hrxn
how to calculate changeHf - correct answer-Use hess's law
how to find change Hrxn using bond energies - correct answer-(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 answer-products change Hf -
reactants change Hf
how to calculate molar bond enthalpy using change Hf - correct answer-1. calculate
change Hrxn using change Hf
2. divide by number of bonds
definition of heat capacity - correct answer-energy in the form of heat required to raise
the temperature of the sample by one degree
what does qp=? - correct answer-change of H
how to calculate heat capacity? - correct answer-heat energy/changeT
how to calculate molar heat capacity - correct answer-heat capacity/moles
how to calculate heat required to raise the temperature using molar heat capacity -
correct answer-=(moles)(molar heat capacity)(changeT)
definition of specific heat - correct answer-heat capacity per gram of substance
how to calculate specific heat - correct answer-(heat capacity)/(mass)
Complete Solutions
definition of thermochemistry - correct answer-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
answer-burning of petroleum for energy
what does the reaction system include? - correct answer-all the chemicals involved in
the reaction
what does the surrounding consist of? - correct answer-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 answer-either as work or as heat
when does the system gain energy as work? - correct answer-when the work is positive
when does the system lose energy as work? - correct answer-when the work is negative
conversion of 1 L*atm to J - correct answer-1 L*atm = 101.325 J
what is it called when the system transfers energy as heat to the suroundings - correct
answer-exothermic
what is the value of q and U in an exothermic reaction - correct answer-negative
what is it called when the system gains energy as heat from the surroundings - correct
answer-endothermic
what is the value of q and U in an endothermic reaction? - correct answer-positive
what does U stand for? - correct answer-the energy of a system
what is the first law of thermodynamics? - correct answer-equivalent to the law of
conservation of energy
state functions - correct answer-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 answer-positive
what is the value of w when system is expanded - correct answer-negative
how do you calculate the energy released as heat - correct answer-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
answer-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 answer-add the
two change Hrxn
how to calculate changeHf - correct answer-Use hess's law
how to find change Hrxn using bond energies - correct answer-(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 answer-products change Hf -
reactants change Hf
how to calculate molar bond enthalpy using change Hf - correct answer-1. calculate
change Hrxn using change Hf
2. divide by number of bonds
definition of heat capacity - correct answer-energy in the form of heat required to raise
the temperature of the sample by one degree
what does qp=? - correct answer-change of H
how to calculate heat capacity? - correct answer-heat energy/changeT
how to calculate molar heat capacity - correct answer-heat capacity/moles
how to calculate heat required to raise the temperature using molar heat capacity -
correct answer-=(moles)(molar heat capacity)(changeT)
definition of specific heat - correct answer-heat capacity per gram of substance
how to calculate specific heat - correct answer-(heat capacity)/(mass)
