WorksheetsEOT Revision
Total questions: 25
Worksheet time: 25mins
Which of the following is/are false statement(s) about entropy?
It is a measure or randomness of a system.
Entropy of a gas is greater than that of a solid.
The greater the disorder in a system, the smaller the entropy.
Dissolving a solid in a solvent, increases the entropy of the system
B & C
For which of the following reaction is/are there a decrease in entropy?
I) I2 (g) → I2 (s)
II) 2 O3 (g) → 3 O3 (g)
III) 2 K (s) + H2O (l) → 2 KOH (aq) + H2 (g)
I
II
III
For a spontaneous exothermic reaction, which of the following statement(s) is/are true?
I) ΔG has a -ve value.
II) ΔH has a -ve value.
III) The reaction will have a decrease in entropy.
I
II
III
The change in concentration of a reactant or a product per unit of time is known as (a) ?
An unstable arrangement of atoms that represents a transition state is known as
(a)
At a certain temperature, the equilibrium constant for the reaction: H2 +Cl2 ⇌ 2 HCl is K. The equilibrium constant for the reaction for the reaction: 1/2 H2 + 1/2 Cl2 ⇌ HCl is ______?
K/2
2
1/K
K^2
√K
A system is at equilibrium when the rate of the forward reaction is equal to the rate of the reverse reactions.
True
False
A student dropped a piece of magnesium ribbon in a flask containing some hydrochloric acid at room temperature. The student observed the experiment for ten minutes but noticed that no reaction occurred. List the three Conditions that must be met for a reaction to occur.
If a process is endothermic and the process creates more order than existed before, the process is________?
always spontaneous
never spontaneous
spontaneous at high temperatures
spontaneous at low temperatures
Without consulting entropy tables, predict the sign of ΔS for the following process:
Pb(s) +Cl2(g) → PbCl2(s)
ΔS > 0
ΔS < 0
ΔS = 0
More Information is needed to make a reasonable prediction
Using the information below, calculate ΔS°rxn for the following reaction:
4Cr(s) + 3O2(g) → 2Cr2O3(s)
Substance, ΔS, J/K.mol
Cr(s), 23.77
O2(g), 205.138
Cr2O3(s), 81.2
548.1 J/K
147.7 J/K
-147.7 J/K
-548.1 J/K
The sign of ΔHrxn and ΔSrxn for several different reactions are given. In which case is the reaction spontaneous at all temperatures?
ΔHrxn < 0 & ΔSrxn < 0
ΔHrxn > 0 & ΔSrxn > 0
ΔHrxn < 0 & ΔSrxn > 0
ΔHrxn > 0 & ΔSrxn < 0
A reaction has a ΔHrxn = -255KJ and ΔSrxn = 211J/K. Calculate ΔG°rxn at 55°C.
2.17*10^3 KJ
69.5*10^3KJ
-267 KJ
-324 KJ
Which statement is true for the freezing of liquid water below 0°C.
ΔH is +ve ; ΔS is -ve ; ΔG is -ve.
ΔH is -ve ; ΔS is -ve ; ΔG is -ve.
ΔH is +ve ; ΔS is +ve ; ΔG is +ve.
ΔH is +ve ; ΔS is -ve ; ΔG is +ve.
Indicate whether the standard entropy change, ΔS°298, is positive, negative or zero. Justify your answer.
State the 3 laws of thermodynamics.
∆G = 0
∆H = T∆S
R has greater entropy than M
Equilibrium exists between M and R
Choose the substance that has the smaller entropy value. Justify your answer.
SO2 (l) or SO2(s)
When a catalyst is added to a chemical reaction, ___________.
it will not be consumed
it doesn't offers an alternative pathway for activation energy
the activation energy will be lowered
it offers an alternative pathway for activation energy
the rate of reaction will increase
Identify the letter that describes the activation energy of the forward reaction.
W
Z
Q
None of the above
Which represents a decrease in entropy?
sublimation of CO2
boiling water
condensation of steam on cold glass
NaCl dissolving in water
What is a spontaneous process ?
slow process
fast process
process that needs an external intervention to occur
process that does not need external intervention to occur / keep happening
There is a natural tendency for energy to spread out.
True
False
ΔG is negative indicates that_______.
reaction is exothermic
reaction is endothermic
reaction is spontaneous
reaction is not spontaneous
