1What factors affect the rate of reaction?
Temperature, Pressure, Surface area, Concentration, Presence of a catalyst
2How does temperature affect the rate of reaction?
Increasing temperature increases the rate of reaction because more particles have energy above the activation energy, leading to more successful collisions.
3How does surface area affect the rate of reaction?
Increasing the surface area increases the rate of reaction because more exposed particles result in more frequent successful collisions.
4How does a catalyst affect the rate of reaction?
A catalyst increases the rate of reaction by providing an alternate pathway with a lower activation energy, allowing more successful collisions.
5How does concentration affect the rate of reaction?
Increasing concentration increases the rate of reaction because there are more reacting particles in the same volume, leading to more frequent successful collisions.
6How does pressure affect the rate of a gaseous reaction?
Increasing pressure increases the rate of reaction because there are more reacting particles in the same volume (or the same number in a smaller volume), resulting in more frequent successful collisions.
7What does the Maxwell-Boltzmann distribution look like for a temperature increase?
A greater proportion of molecules have energy above the activation energy (\(E_a\)).
8What does the Maxwell-Boltzmann distribution look like for the addition of a catalyst?
A greater proportion of molecules have energy above the activation energy (\(E_a\)) due to the lower \(E_a\) pathway provided by the catalyst.
9What is activation energy?
The minimum amount of energy required for a reaction to occur between two reacting particles.
10What is the equation for rate of reaction?
Rate of reaction = Amount of reactant used or product formed / Time (s)
11What units could be used for rate of reaction?
g/s, cm³/s, mol/s
12After completing an experiment, how could you find the rate of reaction using a graph?
Plot time on the X axis and amount of reactant used or product formed on the Y axis, then draw a tangent to find the gradient (\(\Delta Y/\Delta X\)) at a point.
13What is a reversible reaction?
A chemical reaction where the products can react to reform the reactants.
14What is meant by ‘dynamic equilibrium’?
The point in a reversible reaction where the rate of the forwards reaction equals the rate of the backwards reaction, and concentrations remain constant.
15What is Le Chatelier’s principle?
If a change is made to the conditions of a reversible reaction, the position of equilibrium will shift to counteract the change.
16How does increasing the temperature affect the equilibrium position?
It favours the endothermic reaction, shifting equilibrium to the products of the endothermic reaction.
17How does decreasing the temperature affect the equilibrium position?
It favours the exothermic reaction, shifting equilibrium to the products of the exothermic reaction.
18How does increasing the pressure affect the equilibrium position?
It favours the side of the reaction with the least moles of gas, shifting equilibrium to that side.
19How does increasing the concentration of the reactants affect the position of equilibrium?
Equilibrium shifts to the right to increase the concentration of the products.
20The conditions for the Haber process are 450°C and 200 atm. Why are the conditions described as a compromise?
A high temperature increases the rate but decreases yield, while high pressure speeds up the reaction and favours yield but is dangerous and expensive. The conditions balance rate, yield, and practicality.