| What happens to the equilibrium if we increase the concentration of A?
A (aq) + B (aq) ⇌ C (aq) + D (l) | The equilibrium shifts to the right, away from A, and increases the concentration of C. |
| What does rate of reaction mean? | The speed at which reactions take place. |
| What is the rate of reaction measured throuugh? | The quantity of the reactants and products. |
| What are the two equations for the mean rate of reaction? | - Quantity of reactant ÷ time
g/s OR cm³/s OR mol/s
- Quantity of product formed ÷ time |
| What are the three units of rate of reaction? | g/s OR cm³/s OR mol/s |
| If a reaction produces 24g of product of magnesium in 3 minutes, what is the mean rate of reaction? | 3 minutes = 180 seconds.
> 24 ÷ 180
= 0.13 g/s |
| In a reaction, the mass of a product increases by 3kg in 210 seconds, what is the rate? | 3kg = 3,000g.
> 3000 ÷ 210
= 14.29 g/s |
| A reaction produces 200cm³ of gas in 5 minutes. What was the volume of gas at the start of the reaction? | At the start of the reaction, you wont have any gas. This was a trick question. |
| What does the steeper the line show in a rate graph? | The faster the reaction. |
| What is the equation for the mean rate in graphs? | difference in y ÷ difference in x
∆y ÷ ∆x |
| Calculate the mean rate in the first 15 seconds. | (0,0) and (15,50)
∆y ÷ ∆x
> ⁵⁰⁻⁰⁄₁₅-₁₅
> ⁵⁰⁄₁₅
= 3.3cm³/s |
| How do you calculate the mean rate in graphs? | You find the two points that the question indicates. If it says 'in the first...' its from the origin to the value given, however, if it says between ...s and ...s, you have to find the differences of y and x from both co-ordinates.
To find the answer, you need to do the difference in y, divided by the difference in x. |
| What is the collision theory? | The theory that for reactants to react, they need to collide with enough energy and frequency. |
| What is activation energy? | The minimum amount of energy needed for a reaction to start. |
| What are the 5 factors that affect rate of reaction? | Concentration of reactants in solution, temperature, pressure, if a catalyst is present and the surface area of solid reactants. |
| How does the concentration of reactants in a solution affect rate of reaction? | More particles mean that there's an increased chance of collisions, increasing the frequency. |
| How does a catalyst being present affect rate of reaction? | It speeds up the reaction without being used up, by lowering the activation energy. |
| How does the temperature affect rate of reaction? | Particles gain kinetic energy, meaning they are moving more and more frequently colliding. |
| How does the surface area of solid reactants affect rate of reaction? | Things in powder form/ with a larger surface area increase the frequency of collisions. |
| What is the formula for concentration? | Concentration = mass ÷ volume
g/dm³ = g ÷ dm³ |
| What is a catalyst? | A substance that speeds up the rate of reaction by lowering the activation energy, without being used up. |
| What is the hypothesis for HOW DOES CONCENTRATION AFFECT THE RATE OF REACTION? | I believe that increasing the concentration of hydrochloric acid will lead to the rate or reaction being faster. |
| What is the equipment list for HOW DOES CONCENTRATION AFFECT THE RATE OF REACTION? | - Gas syringe.
- Clamp stand.
- Conical flask.
- Measuring cylinder.
- Hydrochloric acid.
- Magnesium ribbons.
- Timer.
- Safety goggles. |
| What is the method for HOW DOES CONCENTRATION AFFECT THE RATE OF REACTION? | 1) Clamp your gas syringe to your clamp standing using your clamp and boss.
2) Measure 50ml if 1 mol/dm³ and pour it into the conical flask.
3) Add in a magnesium ribbon and start the timer, measuring how much gas is produced every 30 seconds for 5 minutes.
4) Repeat the experiment with 50ml of 0.5 mol/dm³ hydrochloric acid instead and compare the results. |
| What is the independent variable for HOW DOES CONCENTRATION AFFECT THE RATE OF REACTION? | Concentration of hydrochloric acid. |
| What is the dependent variable for HOW DOES CONCENTRATION AFFECT THE RATE OF REACTION? | How much gas is produced every 30 seconds. |
| What is the control variable for HOW DOES CONCENTRATION AFFECT THE RATE OF REACTION? | The mass of magnesium that will be used.
The volume of hydrochloric acid that will used. |
| Draw an exothermic reaction profile, labelling everything. | Exothermic reaction profile. |
| Draw an endothermic reaction profile, labelling everything. | Endothermic reaction profile. |
| What are catalysts also used for and why? | Medecine.
- Mass produces product.
- Gain more money on the long run. |
| The diagram below shows the shapes of two different catalysts.
Suggest and explain why shape B is more effective as a catalyst than shape A. | B has a greater surface area, meaning that there are more frequent catalyst-reactant collisions. |
| What is a reversible reaction? | A reaction where the products formed can then react again and form the reactants. It's howed by the symbol ⇌. |
| What is a (dynamic) equilibrium? | The point where the forward and backward reaction in a reversible reaction can react at the same equal ate in a closed system. |
| What is ammonium chloride? | A white solid. |
| What does ammonium chloride break down into? Is it an endothermic or exothermic reaction? | It breaks down into ammonia + hydrogen chloride. It's an endothermic reaction. |
| What happens to the backward reaction if it's exothermic one way? | It's endothermic the other way (and vise versa). |
| What is Le Chatelier's principle? | Something that predicts the effect of changing conditions on a closed system on an equilibrium. |
| What are the three conditions of Le Chatelier's principle? | Concentration, tempertaure and pressure. |
| How does changing the concentration affect an equilibrium? | If the concentration of a solute is changed, the equilibrium shifts AWAY from this side. |
| How does changing the temperature affect an equilibrium? | If the temperature is increased, the equilibrium shifts IN the direction of the endothermic reaction.
However, if the temperature is decreased, the equilibrium shifts IN the direction of the exothermic reaction. |
| How does changing the pressure affect an equilibrium? | If you increase the pressure, the equilibrium shifts to the side that has FEWER particles.
However, if you decrease the pressure, the equilibrium shifts to the side that has MORE particles. |
| What happens to the equilibrium if we increase the concentration of A?
A (aq) + B (aq) ⇌ C (aq) + D (l) | The equilibrium shifts to the right, away from A, and increases the concentration of C. |
| The forward reaction is endothermic, explain what happens to the yield and equilibrium if we increase the temperature.
CH₄ (g) + H₂ (g) ⇌ CO (g) + H₂ (g) | The equilibrium shifts to the right, increasing the yield, because increasing the temperature favours the endothermic, forward reaction. |
| The forward reaction is exothermic. If the temperature is increased, what happens to the yield of CO (g) + H₂ (g) and the equilibrium?
CH₄ (g) + H₂ (g) ⇌ CO (g) + H₂ (g) | The equilibrium shifts to the left, decreasing the yield since it favours the reverse reaction. |
| What happens to the position of the equilibrium if we increase the pressure?
A (g) + 3B (g) ⇌ 2C (g) | A (g) + 3B (g) ⇌ 2C (g)
{________} {__}
4 molecules 2 molecules
The equilibrium shifts to the right since increasing pressure favours the side with fewer molecules. |
| What happens to the position of the equilibrium if we decrease the pressure?
A (g) + B (g) ⇌ C (g) | A (g) + B (g) ⇌ 1C (g)
{________} {__}
2 molecules 1 molecule
The equilibrium shifts to the left since decreasing pressure favours the side with more molecules. |
| What does yield mean? | The amount of product. |
| What does △H mean? | The energy change. |
| What happens to the yield ofC₂H₅OH (g) if we decrease the yield?
CH₄ (g) + H₂O (g) ⇌ C₂H₅OH (g)
△H = -45 kJ per mole. | Increasing the temperature will decrease the yield of C₂H₅OH because the equilibrium shifts to the left, favoring the endothermic reaction.
'△H = -45 kJ per mole' means the forward reaction was exothermic. Since the total energy change is negative, it means it decreased. |
