2020 past paper mistakes Flashcards
What are two measures that can be taken to favour the forward endo reaction?
N2O4 <–> NO2
Decrease in pressure, increase in temperature and the removal of NO2 gas from the vessel
What is the effect of a catalyst on a system in equilibrium?
Has no effect on the equilibrium position. It enables the forward and reverse rates to increase by the same amount
What is the effect of injecting argon gas into a system?
No effect on the equilirbrium or system
Is the forward reaction exo or endo?
Exo, because high Keq at low temperatures would be favouring the production of the products.
Explain, using your understanding of collision theory, how the change at t = 2 minutes
causes the reaction to favour the formation of COCl2.
Structure:
1. Change - volume decrease or pressure increase
2. Increasing the frequency of the collisions within the reaction
3. COCl2 forming reaction requires more reactant particles than its
reverse; this reaction is therefore more dependent on collisions and hence although
both rates increase, the rate of the COCl2 forming reaction will increase more”)
Describe the process of salt undergoing dissolution
Calcium sulfate is an ionic compound which is held together by strong electrostatic forces. Water molecules, which are polar, experience dispersion forces and hydrogen bonding. When the calcium sulfate is placed in water, the ions leave the solid lattice and move into solution. The polarity of water allows for electrostatic interactions between ions and water (diagram). Dissolution occurs when ion dipole forces are more energetically favourable than the existing ionic bonds and intermolecular forces. As such this results in water molecules forming hydration spheres around the ions, allowing dissolves ions to be dispersed in solution.
Explain dissolution of a ionic compound
Compound is ionic which is held together by strong electrostatic forces. Water molecules, which are polar, experience dispersion forces and hydrogen bonding. When the calcium sulfate is placed in water, the ions leave the solid lattice and move into solution. The polarity of water allows for electrostatic interactions between ions and water (diagram).
When does dissolution occur?
Dissolution occurs when ion dipole forces are more energetically favourable than the existing ionic bonds and intermolecular forces. As such this results in water molecules forming hydration spheres around the ions, allowing dissolves ions to be dispersed in solution.
Increasing temp in 1:1 ratio
An increase in pressure is a decrease in volume. According to LCP, the system will favour the side of the equilibrium to minimise the effect of the disturbance. When the pressure is increased, there is an increase in the frequency of collisions hence the rate of the forward and reverse reaction rates increase. Since the gas ratio is 1:1, the position of the eq. will not shift, as neither side is able to reduce the pressure.
Explain why a larger amount of x is produced at a higher temp.
A larger amount of c is produced at a higher temperature because increasing temperature will favour the endothermic reaction, thus favouring the right, according to LCP. Thus the conc. will increase CO as collisional freq increases.
