Intro to Equilibrium

• Chemistry
• Secondary Education

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• Dynamic equilibrium
• Forward reaction
• Backward reaction
• Position of Equilibrium

FOCUS CONCEPTS

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• Why is a "closed system" needed in order to establish a dynamic equilibrium?

FOCUS QUESTION

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A dynamic equilibrium occurs when you have a ____________ reaction in a closed system.

1. reversible
2. irreversible
3. chemical
4. exothermic

In your activity, the reaction is still continuing. For every red square that turns blue, somewhere in the mixture, it is replaced by a blue square turning orange. This is a _______ equilibrium.

1. reversible
2. dynamic
3. constant
4. null

What does the word "dynamic" in dynamic equilibrium mean?

You can show dynamic equilibrium in an equation for a reaction by the use of ___________.

1. an equal sign
2. right arrow
3. left arrow
4. double arrow

• Does this represent a reversible reaction?

A reversible reaction in as state of dynamic equilibrium

Which one is a forward reaction?

1. red to blue
2. blue to red

Which one is a forward reaction?

1. blue to red
2. red to blue

Position of Equilibrium

In the example you've done, the equilibrium mixture contained more red squares than blue ones. Position of equilibrium is a way of expressing this. 

Position of Equilibrium

"The position of equilibrium lies towards the red."

Position of Equilibrium

"The position of equilibrium lies towards the red."

"The position of equilibrium lies towards the right-hand side."

Position of Equilibrium

If the conditions of the experiment change (by altering the relative chances of the forward and back reactions happening), the composition of the equilibrium mixture will also change.

Position of Equilibrium

For example, if changing the conditions produced more blue in the equilibrium mixture, you would say "The position of equilibrium has moved to the left" or "The position of equilibrium has moved towards the blue".

A dynamic equilibrium occurs when you have a reversible reaction in an open system. Nothing can be added to the system or taken away from it apart from energy.

TRUE

FALSE

At equilibrium, the quantities of everything present in the mixture remain constant, although the reactions are still continuing. This is because the rates of the forward and the back reactions are equal.

TRUE

FALSE

If you change the conditions in a way which changes the relative rates of the forward and back reactions, you will change the position of equilibrium - in other words, change the proportions of the various substances present in the equilibrium mixture.

TRUE

FALSE

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