Which of these is an example of a physical change?
2 answers:
You might be interested in
Answer:
The system is not in equilibrium and will evolve left to right to reach equilibrium.
Explanation:
The reaction quotient Qc is defined for a generic reaction:
aA + bB → cC + dD
where the concentrations are not those of equilibrium, but other given concentrations
Chemical Equilibrium is the state in which the direct and indirect reaction have the same speed and is represented by a constant Kc, which for a generic reaction as shown above, is defined:
where the concentrations are those of equilibrium.
This constant is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients divided by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients.
Comparing Qc with Kc allows to find out the status and evolution of the system:
- If the reaction quotient is equal to the equilibrium constant, Qc = Kc, the system has reached chemical equilibrium.
- If the reaction quotient is greater than the equilibrium constant, Qc> Kc, the system is not in equilibrium. In this case the direct reaction predominates and there will be more product present than what is obtained at equilibrium. Therefore, this product is used to promote the reverse reaction and reach equilibrium. The system will then evolve to the left to increase the reagent concentration.
- If the reaction quotient is less than the equilibrium constant, Qc <Kc, the system is not in equilibrium. The concentration of the reagents is higher than it would be at equilibrium, so the direct reaction predominates. Thus, the system will evolve to the right to increase the concentration of products.
In this case:
Q=100,000
100,000 < 4,300,000 (4.3*10⁶)
Q < Kc
<u><em> The system is not in equilibrium and will evolve left to right to reach equilibrium.</em></u>
Explanation:
When magnesium metal burns is heated i the air it forms magnesium oxide.The balanced chemical reaction is given as:
2 moles of magnesium metal when reacts with 1 moles of oxygen it gives 2 moles of magnesium oxide which is white in color.
Some times along with formation of magnesium oxide small amount of magnesium nitride also produced due to which magnesium oxide appears grey in color .The balanced chemical reaction is given as:
3 moles of magnesium combines with 1 mol of nitrogen gas to to give 1 mol of magnesium nitride.