The relationship between the equilibrium constant,
The
Explain, with reference to the information provided, why this reaction proceeds to completion rather than coming to equilibrium. (3 marks)
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The relationship between the equilibrium constant,
The
Explain, with reference to the information provided, why this reaction proceeds to completion rather than coming to equilibrium. (3 marks)
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Calculating
→ The graph shows that large negative values of
→ The
→ This reaction proceeds to completion primarily because of its significantly large, negative
Calculating
→ The graph shows that large negative values of
→ The
→ This reaction proceeds to completion primarily because of its significantly large, negative
Potassium chloride readily dissolves in water. With the use of a labelled diagram, describe the changes in bonding and entropy that occurs during this process. (4 marks)
→ Potassium chloride has a high tendency to dissociate into
→ Water is a dipolar molecule because each atom has a partial charge, as shown in the diagram.
→ The oxygen dipole in water has a partial negative charge and is attracted to the potassium ion. The hydrogen dipoles have a partial negative charge and are attracted to the chloride ion.
→ This attraction breaks the ionic bonds and forms ion-dipole bonds.
→ The entropy of the system is increased as the ionic bonds of the
→ Potassium chloride has a high tendency to dissociate into
→ Water is a dipolar molecule because each atom has a partial charge, as shown in the diagram.
→ The oxygen dipole in water has a partial negative charge and is attracted to the potassium ion. The hydrogen dipoles have a partial negative charge and are attracted to the chloride ion.
→ This attraction breaks the ionic bonds and forms ion-dipole bonds.
→ The entropy of the system is increased as the ionic bonds of the
Over the last 50 years, scientists have recorded increases in the following:
Analyse the factors that affect the equilibrium between carbon dioxide in the air and carbon dioxide in the oceans. In your answer, make reference to the scientists' observations and include relevant equations. (7 marks)
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Fossil fuel combustion:
→ Combustion of fossil fuels releases
→ Increased burning of fossil fuels will contribute to further rises in atmospheric
Carbon dioxide and other climate interactions:
→
→ This is an equilibrium and by Le Chatelier’s principle when a system is changed, the system will adjust to oppose the change.
→ Factors that affect equilibrium in this system are temperature, pressure and concentration of reactants and products.
→ The increase of
→ Scientists have been measuring the level of
→ However, this equilibrium is exothermic and as it causes temperature rises, by Le Chatelier’s principle, the reverse reaction may be subsequently favoured. This would have the effect of decreasing the amount of
→ In summary, if global temperatures continue to rise and
Fossil fuel combustion:
→ Combustion of fossil fuels releases
→ Increased burning of fossil fuels will contribute to further rises in atmospheric
Carbon dioxide and other climate interactions:
→
→ This is an equilibrium and by Le Chatelier’s principle when a system is changed, the system will adjust to oppose the change.
→ Factors that affect equilibrium in this system are temperature, pressure and concentration of reactants and products.
→ The increase of
→ Scientists have been measuring the level of
→ However, this equilibrium is exothermic and as it causes temperature rises, by Le Chatelier’s principle, the reverse reaction may be subsequently favoured. This would have the effect of decreasing the amount of
→ In summary, if global temperatures continue to rise and
The following data apply to magnesium fluoride and magnesium chloride dissolving in water at 298 K.
Compare the effects of enthalpy and entropy on the solubility of these salts. (3 marks)
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→ Magnesium chloride dissolves in water spontaneously as it has a negative
→ Magnesium flouride however does not dissolve in water spontaneously which is shown by its corresponding
→ Both salts have a negative
→ Both salts have a negative
→ This can be compared to magnesium fluoride that has a relatively small negative
→ Magnesium chloride dissolves in water spontaneously as it has a negative
→ Magnesium flouride however does not dissolve in water spontaneously which is shown by its corresponding
→ Both salts have a negative
→ Both salts have a negative
→ This can be compared to magnesium fluoride that has a relatively small negative
Nitric oxide gas (
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a.
b. → From the graph, the forward reaction is endothermic.
→ The activation energy of the forward endothermic reaction is greater than the activation energy of the reverse exothermic reaction.
→ An increase in temperature would cause the rates of both the forward and reverse reaction due to the higher average kinetic energy, resulting in a larger likelihood of a successful collisions.
→ However, the rate of the forward reaction would increase to a higher extent than the reverse reaction, since it is an endothermic reaction.
→ Using
a.
b. → From the graph, the forward reaction is endothermic.
→ The activation energy of the forward endothermic reaction is greater than the activation energy of the reverse exothermic reaction.
→ An increase in temperature would cause the rates of both the forward and reverse reaction due to the higher average kinetic energy, resulting in a larger likelihood of a successful collisions.
→ However, the rate of the forward reaction would increase to a higher extent than the reverse reaction, since it is an endothermic reaction.
→ Using
Consider the equilibrium system shown.
In a laboratory at 23°C, a 100 mL sample of water is held in a beaker and another 100 mL sample is held in a sealed bottle.
Explain the differences in evaporation for these TWO samples. In your answer, consider changes in enthalpy and entropy for this process. (4 marks)
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→ The evaporation of water absorbs energy, hence is an endothermic reaction and results in a positive change in enthalpy (
→ Additionally, the process converts a liquid into a gaseous state, and thus increases the disorder of the system, as a result, entropy increases (
→ Since enthalpy and entropy are both positive, according to
Beaker sample:
→ The evaporation of water in a beaker represents an open system, where vapour molecules are able to escape the system.
→ As a result, there would be a continuous disturbance to the equilibrium, and according to Le Chatelier’s Principle, the equilibrium will shift to counteract the change, and thus produce more gaseous water until there is no liquid water left.
→ Thus, dynamic equilibrium will not be established in a beaker.
Sealed bottle sample:
→ On the other hand, the evaporation of water in a sealed bottle represents a closed system where the water vapour cannot escape from the system.
→ In this reaction liquid water would evaporate, shifting the equilibrium to the right until the rate of the forward reaction and the rate of the reverse reaction is equal.
→ At this point, there would be virtually no change in the concentration of liquid water and gaseous water, and thus dynamic equilibrium will be established.
→ The evaporation of water absorbs energy, hence is an endothermic reaction and results in a positive change in enthalpy (
→ Additionally, the process converts a liquid into a gaseous state, and thus increases the disorder of the system, as a result, entropy increases (
→ Since enthalpy and entropy are both positive, according to
Beaker sample:
→ The evaporation of water in a beaker represents an open system, where vapour molecules are able to escape the system.
→ As a result, there would be a continuous disturbance to the equilibrium, and according to Le Chatelier’s Principle, the equilibrium will shift to counteract the change, and thus produce more gaseous water until there is no liquid water left.
→ Thus, dynamic equilibrium will not be established in a beaker.
Sealed bottle sample:
→ On the other hand, the evaporation of water in a sealed bottle represents a closed system where the water vapour cannot escape from the system.
→ In this reaction liquid water would evaporate, shifting the equilibrium to the right until the rate of the forward reaction and the rate of the reverse reaction is equal.
→ At this point, there would be virtually no change in the concentration of liquid water and gaseous water, and thus dynamic equilibrium will be established.
The relationships between
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a.
b. → For all three reactions
→ The entropy of the reaction,
→ From the relationship
→ At
→ At
→ At
a. At Temperature = 300K:
b. → For all three reactions
→ The entropy of the reaction,
→ From the relationship
→ At
→ At
→ At