Chemistry - Rates Of Reaction 👨🦲 Flashcards
Rate of Reaction
The speed at which a reaction takes place
How do you measure the rate of reaction
• measure how quickly the reactants are used up
• measure how quickly the products are formed
Methods to measure rate of reaction
• change in mass
• volume of gas formed
• formation of a precipitate
What 5 subjects affect the rate of reaction
Temperature, Surface area, Catalysts , Concentration, Pressure
What is necessary conditions need to happen for a reaction to take place?
(2 things )
For chemical bonds to be broken the particles need to collide with
- sufficient energy(often known as activation energy)
- The molecules need to collide in the correct orientation /directiom
What is collision theory?
The theory that chemical reactions can occur ONLY when reacting particles COLLIDE with each other and with suffient energy
What is activation energy?
Activation energy is the minimum amount of energy that particles must have to react. Only reactants with energy equal to or greater than , this value will react.
What is a catalyst?
-Substance that speeds up a reaction
- Is not used up by the reaction
- Lowers activation energy by providing an alternate lower enwrgy pathway
Term given for bubblibg or fizzing
Effervescence
How does pressure increase the rate of reaction?
(Pressure can only be used in experiements involving gases)
gases can be compressed unlike solids/liquids .
So if the pressure is increased there are more reactant particles for a given volume, more collisions, rate of reaction is higher.
What does it mean when the gradient is steep in a graph?
The steeper the gradient in a graph, the faster the reaction
Difference between EXothermic reaction and ENdothermic reaction?
Exothermic reaction transfers energy to the surroundings which is why the temperature of the surroundings increase. As the name suggests , energy EXITS. Endothermic reactions take in energy from the surroundings and as the name suggests, energy enters.
How can you spot the difference between an exothermic and an endothermic graph
Exothermic- The product at the end (after it bypasses the activation energy) would have less energy than the reactant started with
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Endothermic-there is more energy in the product than the reactants started with.
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How to calculate the rate of mean reaction
Total volume of gas collected divided by total time taken to collect gas.
Or another definition quantity of reactant used divided by time taken.
How can you keep the temperature of a reaction mixture constant
•Use a water bath
•Use a greater volume of acid
•Use more acid
Describe the relationship between the mass of carbon dioxide given off in one minute and the concentration of acid
The higher the concentration of the acid, the more carbon dioxide will be given off in one minute. The relation is directly proportional.
Why does concentration increase the rate of reaction
Collisions are more frequent between the two reactants and there will be more collisions in the same volume and a given time.
Two features of (whatever type of) chips that need to be the same to make an experiment fair if you are not testing on different types of chips, but rather testing temperature or concentration
The mass needs to be the same, and it needs to have the same surface area.
What is the rate of reaction?
The speed at which a reaction takes place.
How can the rate of reaction be measured?
By measuring how quickly the reactants are used up or how quickly the products are formed.
What is the first method to measure the rate of reaction?
Change in mass.
How does the change in mass method work?
The mass of the flask and contents decreases as the gas formed leaves the flask.
What is the second method to measure the rate of reaction?
Volume of gas formed.
How is the volume of gas formed measured?
A gas syringe is used to connect to the gas produced during the reaction.
What is the third method to measure the rate of reaction?
Formation of a precipitate.
What indicates the formation of a precipitate?
The solution turns milky/cloudy as the precipitate (insoluble solid) is produced.
What is Collision Theory?
For a reaction to happen, the reacting particles must successfully collide.
What is a successful collision?
A collision that leads to a reaction happening.
What is activation energy?
The minimum energy reacting particles must have when they collide for the reaction to take place.
What factors can change the rate of a reaction?
- Temperature
- Concentration
- Surface area
- Catalyst
How does temperature affect the rate of reaction?
Increasing temperature makes particles move faster, increasing the chance of successful collisions.
What happens to particles at a higher temperature?
Particles have more kinetic energy and move faster.