Which of the following statements is true for a system in equilibrium? A system in chemical equilibrium is heralded by special characteristics. and there is a need to know all the true statements. As a result, there is a need to know all the statements about chemical equilibrium that is false.
I will list all the statements that are true for a system in equilibrium.
There are some basic facts that are true about reversible systems in equilibrium.
But we need to understand first that for a system to be in equilibrium, it must be reversible.
Being reversible then entails it has two reactions going on ; forward and backward reaction.
But we talk about chemical equilibrium when the rate of the forward reaction then equals the rate of backward reaction.
There is a need to monitor a system in dynamic chemical equilibrium and analyse all the observations.
Which of the following statements is true for a system in equilibrium?
A reversible chemical reaction in equilibrium must undergo these properties;
- A chemical system or reaction must be reversible
- A chemical system or reaction must occur in a closed system to attain equilibrium.
- A chemical reaction or system must have both forward and backward reactions occurring at the same rate.
- The properties or concentration of the reactants and products remains constant.
- The presence of a catalyst has no effect on a system at equilibrium but only increases the rates of forward and backward reactions equally.
A chemical system or reaction must be reversible.
The meaning of this is that before we talk about reactions attaining equilibrium the reaction must be able to occur in two directions.
This is because it takes a react that has both forward and backward reactions to have the rates of the two reactions equal.
A chemical reaction must occur in a closed system.
A closed system is a system in which there is no exchange of mass (matter) and energy.
Equilibrium will not be attained in an open system since there is continous or intermittent supply of mass or energy.
A closed system on the other hand can maintain a stable state in the quantity of energy or mass thus enabling equilibrium to be attained with time since equilibrium requires a system to maintain a stable nature with time.
This is the reason Le Chateliers Principle states if the system is disturbed by introduction of external constraints like change in temperature, pressure or temperature..the equilibrium position shifts in order to neutralize the effect and thus go back to equilibrium.
A chemical reaction must have rates of both forward and backward reactions.
Yes, equilibrium in chemical reactions occur when the rate of forward reaction equals the rate of backward reaction.
Equilibrium in simpler terms simply means equal and what should be equal?
The rate of forward reaction must be equal to rate of backward.
When the rates are equal, it seems as if nothing is happening again with respect to time but it means actually that there is same rate of both reactions.
A chemical reaction at equilibrium will have concentration or properties of the system constant
A chemical reaction at equilibrium will have no net change in the properties of the system with respect to time.
This means that once equilibrium is reached by rates of reactions being equal; concentration or properties of the system do not necessarily become the same but constant.
Let me explain with a little example;
Take a look at this equation.
N2 + 3H2===2NH3
If the volume ratio at equilibrium is 30cm3 to 20cm3, it needs to remain constant but not necessarily equal.
What needs to be equal or same is the rate of both forward and backward reaction.
The addition of a Catalyst has no effect on equilibrium position.
Adding a Catalyst is simply to speed up rates of chemical reactions.
In chemical equilibrium, a Catalyst increases the rates of both forward and backward reactions and thus has no effect on equilibrium position.
What it means is that adding a Catalyst does not shift equilibrium position to the left or right but only increases the rates of both reactions.
So therefore, a Catalyst cannot influence or favor any particular reaction but increases the rate of both favoured reaction and the other one not favoured though it may increase more the rate of favoured reaction.