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Module 5: Physical Chemistry and Transition Elements
5.3 Enthalpy, Entropy and Free Energy
5.3.2 Entropy changes
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Cards (30)
What does entropy measure in thermodynamics?
Disorder or randomness
Entropy is lowest in solids because their
molecules
are highly ordered.
True
Gases have the highest entropy because their molecules are highly
disordered
Processes that decrease disorder result in a decrease in
entropy
.
True
Why do solids have low entropy?
Highly ordered structure
Entropy is lowest in
solids
because their molecules are highly ordered.
A higher entropy value indicates greater
disorder
The entropy of a solid is
low
because its molecular arrangement is highly ordered.
The entropy of a liquid is
moderate
because its molecular arrangement is less ordered than a solid.
The entropy of a gas is
high
because its molecular arrangement is highly disordered.
Increasing temperature generally increases
entropy
.
True
Mixing substances or solutions increases
entropy
by creating a more random distribution of particles.
Solids have
low
entropy because their molecules are arranged in a highly ordered crystalline structure.
What is the formula for calculating entropy changes using standard entropy values (
Δ
S
∘
\Delta S^\circ
Δ
S
∘
)?
Δ
S
∘
=
\Delta S^\circ =
Δ
S
∘
=
∑
n
i
S
i
∘
(
p
r
o
d
u
c
t
s
)
−
∑
n
j
S
j
∘
(
r
e
a
c
t
a
n
t
s
)
\sum n_{i} S_{i}^\circ(products) - \sum n_{j} S_{j}^\circ(reactants)
∑
n
i
S
i
∘
(
p
ro
d
u
c
t
s
)
−
∑
n
j
S
j
∘
(
re
a
c
t
an
t
s
)
Higher temperatures generally increase entropy changes.
True
The reaction
2 \ce{H2(g)} +
\ce{O2(g)} \to 2 \ce{H2O(l)}
has a negative entropy change.
True
A process is more likely to occur spontaneously if it results in an increase in
entropy
In which state of matter is entropy highest?
Gas
Why does mixing substances increase entropy?
Creates random distribution
Entropy helps predict the
spontaneity
of physical and chemical processes.
Gases have the highest entropy due to their highly
disordered
molecular arrangement.
True
What is the relationship between entropy and spontaneity in thermodynamics?
Increase in entropy leads to spontaneity
Entropy helps predict the spontaneity of physical and chemical processes.
True
A process is more likely to occur spontaneously if it results in an increase in
entropy
.
True
Entropy is denoted by the symbol
S
.
True
Order the states of matter from lowest to highest entropy:
1️⃣ Solid
2️⃣ Liquid
3️⃣ Gas
Phase changes from solid to liquid to gas typically increase
entropy
.
True
Gases have the highest entropy due to their highly disordered
molecular
arrangement.
True
In the formula for
Δ
S
∘
\Delta S^\circ
Δ
S
∘
,
n
i
n_{i}
n
i
and
n
j
n_{j}
n
j
represent the stoichiometric coefficients of the products and reactants, respectively.
Transitions from solid to liquid to gas typically increase
entropy
due to the more disordered molecular arrangement.