Chem 162 Exam Questions with
Verified Solutions
exothermic reaction - ANS-a chemical reaction that releases energy to its surroundings
"Heat" is best described as - ANS-the energy transferred as a result of a temperature
difference
endothermic reaction - ANS-A reaction that ABSORBS energy in the form of heat
Iodine Vapor depositing on a cool surface - ANS-exothermic
water condensing on a cold glass - ANS-exothermic
propane burning - ANS-exothermic
dry ice subliming - ANS-physical, endothermic reaction
work - ANS--P delta V
the horizontal part of heating curve indicates:
- the mass of material is irrelivant
the energy being added is being used to overcome intermolecular forces
there is no net energy change during phase changes
the material can no longer fain energy
the temperature is rising - ANS-there is no net energy change during phase changes
solid to gas is called - ANS-sublimation
liquid to gas is called - ANS-evaporation
liquid to solid is called - ANS-freezing
solid to liquid - ANS-melting
given = masses of each, same T initial and same amount energy lost, which will end
with the lowest temperature?
highest or lowest Cp (specific heat) - ANS-A copper pot (lowest specific heat (Cp)
which species has a standard enthalpy of formation of zero (delta H of f degrees)
- C (s, diamond)
, - NaCl (s)
- H2 (g)
- Br (l)
- Al2 (s) - ANS-H2 (g)
which of the following ways is not a way to calculate enthalpy of a reaction?
using enthalpies of formation
the temperature change of a reaction is the enthalpy of reaction
the using a calorimeter to determine q cal, relate that. to q run and then delta h rxn
apply hess law using a series of known enthalpy of reactions to achieve an overall
enthalpy of reaction
using bond energies of the reactants and products - ANS-- the temperature change of a
reaction is the enthalpy of reaction
which of the following processes is spontaneous?
- you get an a in this course
- the Tupperware drawer is organized
- a broken touchscreen fixes itself
- rust turns into iron metal and oxygen gas
- sugar dissolves in tea - ANS-- sugar dissolves in tea
in a spontaneous process, the entropy of the ______________ always increases
- universe
- surroundings
- system
- system and the universe
- system, surroundings, and universe - ANS-- universe
at 0 K the entropy of a perfect crystal is
<0
>0
=0 - ANS-= 0
positive entropy - ANS-more disorder
In an exothermic reaction, the external entropy (entropy of the surroundings)
__________ - ANS-increases
endothermic rxn and q - ANS-q is +
exothermic rxn and q - ANS-q is -
w = + - ANS-work done ON system (delta v is -)
w = - - ANS-work done BY system
Verified Solutions
exothermic reaction - ANS-a chemical reaction that releases energy to its surroundings
"Heat" is best described as - ANS-the energy transferred as a result of a temperature
difference
endothermic reaction - ANS-A reaction that ABSORBS energy in the form of heat
Iodine Vapor depositing on a cool surface - ANS-exothermic
water condensing on a cold glass - ANS-exothermic
propane burning - ANS-exothermic
dry ice subliming - ANS-physical, endothermic reaction
work - ANS--P delta V
the horizontal part of heating curve indicates:
- the mass of material is irrelivant
the energy being added is being used to overcome intermolecular forces
there is no net energy change during phase changes
the material can no longer fain energy
the temperature is rising - ANS-there is no net energy change during phase changes
solid to gas is called - ANS-sublimation
liquid to gas is called - ANS-evaporation
liquid to solid is called - ANS-freezing
solid to liquid - ANS-melting
given = masses of each, same T initial and same amount energy lost, which will end
with the lowest temperature?
highest or lowest Cp (specific heat) - ANS-A copper pot (lowest specific heat (Cp)
which species has a standard enthalpy of formation of zero (delta H of f degrees)
- C (s, diamond)
, - NaCl (s)
- H2 (g)
- Br (l)
- Al2 (s) - ANS-H2 (g)
which of the following ways is not a way to calculate enthalpy of a reaction?
using enthalpies of formation
the temperature change of a reaction is the enthalpy of reaction
the using a calorimeter to determine q cal, relate that. to q run and then delta h rxn
apply hess law using a series of known enthalpy of reactions to achieve an overall
enthalpy of reaction
using bond energies of the reactants and products - ANS-- the temperature change of a
reaction is the enthalpy of reaction
which of the following processes is spontaneous?
- you get an a in this course
- the Tupperware drawer is organized
- a broken touchscreen fixes itself
- rust turns into iron metal and oxygen gas
- sugar dissolves in tea - ANS-- sugar dissolves in tea
in a spontaneous process, the entropy of the ______________ always increases
- universe
- surroundings
- system
- system and the universe
- system, surroundings, and universe - ANS-- universe
at 0 K the entropy of a perfect crystal is
<0
>0
=0 - ANS-= 0
positive entropy - ANS-more disorder
In an exothermic reaction, the external entropy (entropy of the surroundings)
__________ - ANS-increases
endothermic rxn and q - ANS-q is +
exothermic rxn and q - ANS-q is -
w = + - ANS-work done ON system (delta v is -)
w = - - ANS-work done BY system
