paper 2 chemistry

• [6.1]

  What is the rate of reaction?

  The rate of reaction is how quickly a reaction takes place.
• [6.1]

  Give the formula for rate of reaction.

  Rate of reaction = Quantity of product/reactant / Time taken
• [6.1]

  Why does the rate of reaction decrease over time?

  The rate of reaction decreases over time because the amount of products decreases as they are used up.
• [6.2]

  Give the 4 factors affecting rate of reaction.

  The 4 factors affecting rate of reaction are:

  - Temperature

  - Surface area

  - Concentration

  - Catalysts
• [6.2]

  What is collision theory?

  Collision theory is the idea that in order to react, particles must collide with sufficient energy (the activation energy).
• [6.2]

  What is a catalyst?

  A catalyst speeds up the rate of reaction without being used up, offering an alternative pathway for particles.
• [6.2]

  How does a catalyst speed up the rate of reaction?

  A catalyst speeds up the rate of reaction by offering an alternative pathway for particles to react with a lower activation energy, increasing the number of successful collisions.
• [6.3]

  Describe how to find the rate of reaction over a given time within a graph.

  To find the rate of reaction over a given time within a graph:

  - Find the amount of substance used/produced in the given time frame

  - Find the rate of reaction using the formula
• [6.3]

  Describe how to find the rate of reaction at a specific given time within a graph.

  To find the rate of reaction at a specific given time within a graph:

  - Draw a tangent at the given time

  - Find the amount of substance used/produced across the tangent

  - Find the time across the tangent

  - Find the rate of reaction using the formula
• [6.4]

  What are reversible reactions?

  Reversible reactions are ones in which both sides of the equation can react to form the others.
• [6.4]

  What is equilibrium?

  Equilibrium occurs when both the rate of forward and backward reaction is equal within a reversible reaction.
• [6.4]

  Which reaction is favoured in a reversible reaction if the point of equilibrium lies to the right?

  If the point of equilibrium lies to the right in a reversible reaction, the forward reaction is favoured.
• [6.4]

  Which reaction is favoured in a reversible reaction if the point of equilibrium lies to the left?

  If the point of equilibrium lies to the left in a reversible reaction, the backward reaction is favoured.
• [6.4]

  Which type of system can equilibrium be reached in?

  Equilibrium can be reached in a closed system, as the conditions and mass of substances are constant.
• [6.5]

  What is Le Chatelier's principle?

  Le Chatelier's principle is the idea that if changes are made to the conditions of a reversible reactions, the point of equilibrium shifts to counteract those changes.
• [6.5]

  What effect would increasing the temperature have on a reversible reaction?

  Increasing the temperature in a reversible reaction would cause the equilibrium to shift and favour the endothermic side, taking in energy to counteract the heating.
• [6.5]

  What effect would decreasing the temperature have on a reversible reaction?

  Decreasing the temperature in a reversible reaction would cause the equilibrium to shift and favour the exothermic side, releasing energy to counteract the cooling.
• [6.5]

  What effect would increasing the pressure have on a reversible reaction?

  Increasing the pressure in a reversible reaction would cause the equilibrium to shift and favour the side with fewer molecules, decreasing the concentration and therefore pressure.
• [6.5]

  What effect would decreasing the pressure have on a reversible reaction?

  Decreasing the pressure in a reversible reaction would cause the equilibrium to shift and favour the side with more molecules, increasing the concentration and therefore pressure.
• [6.5]

  What effect would increasing the concentration of one side have on a reversible reaction?

  Increasing the concentration of one side in a reversible reaction would cause the equilibrium to shift and favour the opposite side, decreasing the concentration.
• [7.1]

  What is a hydrocarbon?


  A hydrocarbon is a molecule composed entirely of hydrogen and carbon.
• [7.1]

  What is a homologous series?

  A homologous series is a collection of compounds with a general formula.
• [7.1]

  What are alkanes?


  Alkanes are a homologous series of saturated hydrocarbons.
• [7.1]

  Why are alkanes described as saturated?

  Alkanes are described as saturated as every carbon atom has a single covalent bond with 4 other atoms, meaning it has no free bonds.
• [7.1]

  Give the general formula for alkanes.


  The general formula for alkanes is CₙH₂ₙ₊₂.
• [7.1]

  Name the first 4 alkanes.

  The first 4 alkanes are:

  - Methane

  - Ethane

  - Propane

  - Butane
• [7.1]

  What is an isomer?

  An isomer is a structural variation of a molecule with the same molecular formula (the atoms are arranged differently).
• [7.2]

  How does chain length affect an alkane?

  As chain length increases in an alkane:

  - Boiling point increases

  - Viscosity increases

  - Flammability increases
• [7.2]

  What is the main usage of hydrocarbons?

  The main usage of hydrocarbons is as fuel through combustion.
• [7.2]

  Give the word equation for complete combustion of a hydrocarbon.

  Hydrocarbon + Oxygen → Carbon dioxide + Water
• [7.3]

  What is crude oil?

  Crude oil is a mixture of compounds, mainly hydrocarbons.
• [7.3]

  How is crude oil formed?

  Crude oil is formed as a result of dead organic matter compressing over millions of years.
• [7.3]

  Why is crude oil considered a finite resource?

  Crude oil is considered a finite resource due to the fact that it takes millions of years to form.
• [7.3]

  Describe fractional distillation of crude oil.

  In fractional distillation of crude oil:

  - The crude oil is heated until it is largely gaseous

  - The gaseous mixture is passed into a fractionating column

  - The fractionating column is heated at the bottom, and cools with height

  - As the gases travel up the column, they condense at different levels due to differing boiling points, separating them
• [7.4]

  What is cracking?

  Cracking is a thermal decomposition reaction in which longer chain hydrocarbons are broken down into more useful ones.
• [7.4]

  What are the 2 types of cracking?

  The 2 types of cracking are:

  - Catalytic

  - Steam
• [7.4]

  Describe the steps for catalytic cracking.

  In catalytic cracking:

  - The hydrocarbon is vaporised

  - The hydrocarbon is passed over a catalyst, splitting it
• [7.4]

  Describe the steps for steam cracking.

  In steam cracking:

  - The hydrocarbon is vaporised

  - The hydrocarbon is mixed with steam and heated, splitting it
• [7.4]

  Give the general equation for cracking.

  Longer chain alkane → Shorter chain alkane + Alkene
• [7.4]

  What are alkenes?

  Alkenes are a homologous series of unsaturated hydrocarbons.