Question

practice: le chateliers principle
directions: complete the chart below by predicting what changes each stress will cause to the reaction at equilibrium, according to le chateliers principle. under \direction favored\, write \forward or reverse\. for the remaining columns, write \increase, decrease, or stays the same\. an example has been done in the first row for you.
reaction #1: $2so_2(g) + o_2(g) \
ightleftharpoons 2so_3(g)$

stress

direction favored

$so_2$

$o_2$

$so_3$

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add $so_2$

forward

-

decrease

increase

add $o_2$

forward

-

add $so_3$

-

remove $so_2$

-

remove $o_2$

-

remove $so_3$

-

increase pressure

decrease pressure

Explanation:

Step1: Apply Le Chatelier's Principle (Add O₂)

Adding reactant favors forward reaction. $\ce{O2}$ is added (marked '-'), so $\ce{[SO2]}$ decreases, $\ce{[SO3]}$ increases.

Step2: Apply Le Chatelier's Principle (Add SO₃)

Adding product favors reverse reaction. $\ce{[SO3]}$ is added (marked '-'), so $\ce{[SO2]}$ increases, $\ce{[O2]}$ increases.

Step3: Apply Le Chatelier's Principle (Remove SO₂)

Removing reactant favors reverse reaction. $\ce{[SO2]}$ is removed (marked '-'), so $\ce{[O2]}$ increases, $\ce{[SO3]}$ decreases.

Step4: Apply Le Chatelier's Principle (Remove O₂)

Removing reactant favors reverse reaction. $\ce{[O2]}$ is removed (marked '-'), so $\ce{[SO2]}$ increases, $\ce{[SO3]}$ decreases.

Step5: Apply Le Chatelier's Principle (Remove SO₃)

Removing product favors forward reaction. $\ce{[SO3]}$ is removed (marked '-'), so $\ce{[SO2]}$ decreases, $\ce{[O2]}$ decreases.

Step6: Apply Le Chatelier's Principle (Increase pressure)

Fewer gas moles (3 reactant → 2 product) favor forward reaction. $\ce{[SO2]}$ decreases, $\ce{[O2]}$ decreases, $\ce{[SO3]}$ increases.

Step7: Apply Le Chatelier's Principle (Decrease pressure)

More gas moles favor reverse reaction. $\ce{[SO2]}$ increases, $\ce{[O2]}$ increases, $\ce{[SO3]}$ decreases.

Answer:

Stress	Direction Favored	[SO₂]	[O₂]	[SO₃]
Add O₂	forward	decrease	-	increase
Add SO₃	reverse	increase	increase	-
Remove SO₂	reverse	-	increase	decrease
Remove O₂	reverse	increase	-	decrease
Remove SO₃	forward	decrease	decrease	-
Increase pressure	forward	decrease	decrease	increase
Decrease pressure	reverse	increase	increase	decrease