OAT EXAM QUESTIONS AND ANSWERS.
Conduction - CORRECT ANSWER direct transfer of energy from molecule to molecule via direct
molecular collsions
What are the best and worst conductors? - CORRECT ANSWER Worst= gases
Best= metals
Convection - CORRECT ANSWER heat transfer by physical motion; only takes place in fluids and gases.
Heat energy is transferred AWAY from the source.
Radiation - CORRECT ANSWER transfer of energy by electromagnetic waves. Radiation can travel
through a hard vacuum.
Ex: energy from sun
specific heat - CORRECT ANSWER c, amount of heat energy needed to raise the temperature of 1kg by
on degree K.
What is the specific heat of water? - CORRECT ANSWER 4186 J/kg*K
Heat transfer formula - CORRECT ANSWER Q=mc(Tf-Ti)
Heat of transformation from solid to liquid - CORRECT ANSWER heat of fusion
Heat of transformation from liquid to gas - CORRECT ANSWER heat of vaporization
Temperature Definition - CORRECT ANSWER average kinetic energy of the system
Pressure definition - CORRECT ANSWER Force per unit surface area (F/A)
,STP Conditions - CORRECT ANSWER 273 K
1 atm
1 mole gas --> 22.4 L
Ideal Gas law - CORRECT ANSWER PV=nRT
n= 8.31 J/K*mol
Internal Energy of Monoatomic ideal gas - CORRECT ANSWER U = (3/2)nR(Tf-Ti)
*if temperature stays constant, the internal energy stays constant*
How does Q change when heat is added or removed from a system? - CORRECT ANSWER Heat added:
Q>0
Heat removed: Q<0
When is work positive? - CORRECT ANSWER When work is done by the gas (when the gas loses energy)
When is work negative? - CORRECT ANSWER When work is done on the gas (when the gas gains energy)
First law of thermodynamics - CORRECT ANSWER Change in Internal Energy (U) = Q - W
Work in thermodynamic process - CORRECT ANSWER work done by a sample of gas is equal to the area
enclosed by its P-V curve
When the volume of a sample of gas decreases, what is the resulting work? - CORRECT ANSWER Work is
done on the gas, therefore the work will be negative
Cyclic processes (Pressure and Volume) - CORRECT ANSWER total work done by the gas is area enclosed
Final Internal energy = Initial internal energy
,Isothermal process - CORRECT ANSWER temperature remains constant
As pressure of gas increases, the volume decreases (and vice-versa)
*if ideal gas, then Q = W
Isobaric process - CORRECT ANSWER Pressure remains constant
As volume increases, temperature increases
W=P(Vf-Vi)
Isovolumetric process - CORRECT ANSWER volume stays constant
Work = 0
U=Q
Adiabatic expansion/compression - CORRECT ANSWER No heat transfer into/out of the system
Q=0
U = -W
irreversible process - CORRECT ANSWER all real processes; proceed in definite time order
Ex: dropping a glass onto the floor and it shatters into many pieces, this can't be undone
reversible process - CORRECT ANSWER system can run initial to final state or final state to initial state
along the same path
Entropy Definition - CORRECT ANSWER degree of disorder of a system
Second Law of thermodynamics - CORRECT ANSWER any thermodynamic process that moves from one
equilibrium state to another, the entropy of the system and its surrounding environment together will
either increase or remain unchanged.
Reaction Rate - CORRECT ANSWER = change in concentration/time for change to occur
, Rate Law - CORRECT ANSWER rate = k[A]^x[B]^y
overall order = x+y
Temperature & Reaction rates - CORRECT ANSWER rate of reaction will double every +10 degree C
Catalysts - CORRECT ANSWER -are not consumed or altered in reaction process
-lowers activation energy
Homogenous catalyst - CORRECT ANSWER catalyst is in same phase as reactants
Heterogenous Catalyst - CORRECT ANSWER catalyst is in different phase as reactants
Equilibrium Constant Characteristics - CORRECT ANSWER -Pure solids or liquids do not appear in
equilibrium constant expression
-Larger Kc (>1000) --> equilibrium favors products
-Smaller Kc (<-1000) --> equilibrium favors reactants
-Intermediate Kc (-1000 to 1000) --> reactants and products are present in similar amounts at
equilibrium
Le Chatelier's Principle - CORRECT ANSWER when a stress is applied to a system at equilibrium, the
system will adjust to minimize the effect of the stress
When more reactant is added, equilibrium will shift towards the products
When more product is added, equilibrium will shift towards the reactants
increase in pressure --> shift equilibrium to lower number of moles present
increase in volume --> equilibrium shift to higher moles present
Conduction - CORRECT ANSWER direct transfer of energy from molecule to molecule via direct
molecular collsions
What are the best and worst conductors? - CORRECT ANSWER Worst= gases
Best= metals
Convection - CORRECT ANSWER heat transfer by physical motion; only takes place in fluids and gases.
Heat energy is transferred AWAY from the source.
Radiation - CORRECT ANSWER transfer of energy by electromagnetic waves. Radiation can travel
through a hard vacuum.
Ex: energy from sun
specific heat - CORRECT ANSWER c, amount of heat energy needed to raise the temperature of 1kg by
on degree K.
What is the specific heat of water? - CORRECT ANSWER 4186 J/kg*K
Heat transfer formula - CORRECT ANSWER Q=mc(Tf-Ti)
Heat of transformation from solid to liquid - CORRECT ANSWER heat of fusion
Heat of transformation from liquid to gas - CORRECT ANSWER heat of vaporization
Temperature Definition - CORRECT ANSWER average kinetic energy of the system
Pressure definition - CORRECT ANSWER Force per unit surface area (F/A)
,STP Conditions - CORRECT ANSWER 273 K
1 atm
1 mole gas --> 22.4 L
Ideal Gas law - CORRECT ANSWER PV=nRT
n= 8.31 J/K*mol
Internal Energy of Monoatomic ideal gas - CORRECT ANSWER U = (3/2)nR(Tf-Ti)
*if temperature stays constant, the internal energy stays constant*
How does Q change when heat is added or removed from a system? - CORRECT ANSWER Heat added:
Q>0
Heat removed: Q<0
When is work positive? - CORRECT ANSWER When work is done by the gas (when the gas loses energy)
When is work negative? - CORRECT ANSWER When work is done on the gas (when the gas gains energy)
First law of thermodynamics - CORRECT ANSWER Change in Internal Energy (U) = Q - W
Work in thermodynamic process - CORRECT ANSWER work done by a sample of gas is equal to the area
enclosed by its P-V curve
When the volume of a sample of gas decreases, what is the resulting work? - CORRECT ANSWER Work is
done on the gas, therefore the work will be negative
Cyclic processes (Pressure and Volume) - CORRECT ANSWER total work done by the gas is area enclosed
Final Internal energy = Initial internal energy
,Isothermal process - CORRECT ANSWER temperature remains constant
As pressure of gas increases, the volume decreases (and vice-versa)
*if ideal gas, then Q = W
Isobaric process - CORRECT ANSWER Pressure remains constant
As volume increases, temperature increases
W=P(Vf-Vi)
Isovolumetric process - CORRECT ANSWER volume stays constant
Work = 0
U=Q
Adiabatic expansion/compression - CORRECT ANSWER No heat transfer into/out of the system
Q=0
U = -W
irreversible process - CORRECT ANSWER all real processes; proceed in definite time order
Ex: dropping a glass onto the floor and it shatters into many pieces, this can't be undone
reversible process - CORRECT ANSWER system can run initial to final state or final state to initial state
along the same path
Entropy Definition - CORRECT ANSWER degree of disorder of a system
Second Law of thermodynamics - CORRECT ANSWER any thermodynamic process that moves from one
equilibrium state to another, the entropy of the system and its surrounding environment together will
either increase or remain unchanged.
Reaction Rate - CORRECT ANSWER = change in concentration/time for change to occur
, Rate Law - CORRECT ANSWER rate = k[A]^x[B]^y
overall order = x+y
Temperature & Reaction rates - CORRECT ANSWER rate of reaction will double every +10 degree C
Catalysts - CORRECT ANSWER -are not consumed or altered in reaction process
-lowers activation energy
Homogenous catalyst - CORRECT ANSWER catalyst is in same phase as reactants
Heterogenous Catalyst - CORRECT ANSWER catalyst is in different phase as reactants
Equilibrium Constant Characteristics - CORRECT ANSWER -Pure solids or liquids do not appear in
equilibrium constant expression
-Larger Kc (>1000) --> equilibrium favors products
-Smaller Kc (<-1000) --> equilibrium favors reactants
-Intermediate Kc (-1000 to 1000) --> reactants and products are present in similar amounts at
equilibrium
Le Chatelier's Principle - CORRECT ANSWER when a stress is applied to a system at equilibrium, the
system will adjust to minimize the effect of the stress
When more reactant is added, equilibrium will shift towards the products
When more product is added, equilibrium will shift towards the reactants
increase in pressure --> shift equilibrium to lower number of moles present
increase in volume --> equilibrium shift to higher moles present
