CHEM121 SIMPLIFIED EXAM
REVISION STUDYGUIDE
Exothermic
Loses heat (-q)
Endothermic
Uses heat (+q)
internal energy
E = KE + PE
If a system loses energy, is work done by the system
positive or negative?
Negative, if q<0, then w<0
Work
w = -PΔV
If ΔV is positive, is work positive or negative?
Negative. ΔV>0, w<0
Enthalpy/ heat of reaction
ΔH=ΔE+PΔV or ΔHrxn=Hprod-Hreac or ΔH=qp
Is a positive change in enthalpy (ΔH) exothermic or
endothermic?
Endothermic
How can we change the KE of an ideal gas?
Change its temperature. KE=(3/2)RT
At constant pressure, will heating an ideal gas
increase or decrease volume?
Increase. Heating means expansion
In the specific heat capacity equations, R is equal to
_____________.
Cp=(5/2)R and Cv=(3/2)R ,where R=8.3145 J/K/mol
, Which of q, w, E, H are state functions?
E and H. Meaning, ΔE and ΔH values from initial to final
state will be constant no matter the steps to get there.
Calorimetry
The science of measuring heat
What is the relationship between heat and
temperature?
q is directly proportional to ΔT
What variable is required to determine the heat
capacity of a substance?
The amount of the substance in g or mol.
Does PV work occur at constant volume?
No, ΔE=nCvΔT
Hess's Law
Change in ENTHALPY is the same whether reaction takes
place in one step or a series of steps
Define the units for Graham's Law (R1/R2)=√(M2/M1)
R in mol/sec, M in g/mol
Which will have a greater average velocity? A gas with
a big or small molar mass?
Smaller molar mass means greater average velocity
In the average and root mean square velocity
equations, define R and M
R=8.3145 J/K/mol , M is in kg/mol
James Maxwell
EMR is a form of energy transmission where electric E
and magnetic H fields are propagated as waves through
empty space or through a medium like glass
Define the units used in λv=c
λ in meters, v in /s or Hz, c=2.998E8 m/s
Max Planck
REVISION STUDYGUIDE
Exothermic
Loses heat (-q)
Endothermic
Uses heat (+q)
internal energy
E = KE + PE
If a system loses energy, is work done by the system
positive or negative?
Negative, if q<0, then w<0
Work
w = -PΔV
If ΔV is positive, is work positive or negative?
Negative. ΔV>0, w<0
Enthalpy/ heat of reaction
ΔH=ΔE+PΔV or ΔHrxn=Hprod-Hreac or ΔH=qp
Is a positive change in enthalpy (ΔH) exothermic or
endothermic?
Endothermic
How can we change the KE of an ideal gas?
Change its temperature. KE=(3/2)RT
At constant pressure, will heating an ideal gas
increase or decrease volume?
Increase. Heating means expansion
In the specific heat capacity equations, R is equal to
_____________.
Cp=(5/2)R and Cv=(3/2)R ,where R=8.3145 J/K/mol
, Which of q, w, E, H are state functions?
E and H. Meaning, ΔE and ΔH values from initial to final
state will be constant no matter the steps to get there.
Calorimetry
The science of measuring heat
What is the relationship between heat and
temperature?
q is directly proportional to ΔT
What variable is required to determine the heat
capacity of a substance?
The amount of the substance in g or mol.
Does PV work occur at constant volume?
No, ΔE=nCvΔT
Hess's Law
Change in ENTHALPY is the same whether reaction takes
place in one step or a series of steps
Define the units for Graham's Law (R1/R2)=√(M2/M1)
R in mol/sec, M in g/mol
Which will have a greater average velocity? A gas with
a big or small molar mass?
Smaller molar mass means greater average velocity
In the average and root mean square velocity
equations, define R and M
R=8.3145 J/K/mol , M is in kg/mol
James Maxwell
EMR is a form of energy transmission where electric E
and magnetic H fields are propagated as waves through
empty space or through a medium like glass
Define the units used in λv=c
λ in meters, v in /s or Hz, c=2.998E8 m/s
Max Planck
