Controlling Reactions Flashcards
What is rate of reaction
It is the measure of how quickly reactants are used up or products are formed
What factors affect rate of reaction
Temperature, Concentration (pressure when talking about gas), surface area and the presence of a catalyst
What is collision theory
Collision theory states that a reaction can occur only when reactant particles collide with each other, with enough force. The more frequent collisions there are, the higher chance of successful collisions.
What is activation energy
The minimum amount of energy needed for a reaction to happen between two particles.
How does temperature affect the rate of reaction
Increased temperature increases the kinetic energy in the particles. This increases the frequency of collisions therefore increasing the chance of successful collisions, increasing the rate of reaction.
How does concentration (pressure) affect rate of reaction
Increased concentration (pressure) decreases the space meaning there are more particles in one area, much closer together. This increases the frequency of collisions therefore increasing the chance of successful collisions, increasing the rate of reaction.
How does surface area affect rate of reaction
A larger surface area means there are more exposed particles to . This increases the frequency of collisions therefore increasing the chance of successful collisions, increasing the rate of reaction.
How does a catalyst affect the rate of reaction
Catalysts reduce the activation energy of a reaction meaning it can occur at lower temperatures, faster. It does not get used up (remains unchanged) and catalysts catalyse specific reactions.
Name a reaction where you would measure the products
- magnesium and hydrochloric acid –> measure the hydrogen gas
Really any reaction where there is gas that can be collected or there is something that can be weighed
Name a reaction where you would measure the reactants
Calcium carbonate in sulphuric acid
measure the decrease in mass
How do you calculate rate of reaction
The amount of product/reactant divided by the time
measured in g/s or kg/s or cm3/min ect
OR
1 divided by the reaction time (mean time)
used when its difficult to measure either.
Word and symbol equation for magnesium dissolved in hydrochloric acid
Magnesium + Hydrochloric acid ~~> Magnesium chloride and Hydrogen
Mg(s) + 2HCl(aq)~> MgCl₂(aq) + H₂(g)
Word and symbol equation for calcium carbonate and sulphuric acid
Calcium carbonate + sulphuric acid ~> Calcium sulphate + Carbon dioxide + water
CaCO₃(s)+ H₂SO₄(aq)~> CaSO₄(aq) +CO₂ (g)+ H₂O(l)
Word and symbol equation for the decomposition of hydrogen peroxide
hydrogen peroxide~> water and oxygen
2H₂O₂(aq) ~> 2H₂O(l) + O₂(g)
Word and symbol equation for sodium thiosulfate and hydrochloric acid
sodium thiosulfate + hydrochloric acid ~> Sulphur + sodium chloride + water + sulphur dioxide
Na₂S₂O₃ + HCl ~> S + 2NaCl + H₂O + SO₂
