Rate of reactions Flashcards
How do you work out the rate of a chemical reaction
The quantity of reactant used or product formed / time taken
What is the unit for rates of reaction
Grams per cm ³ (g/cm ³)
HT - moles per second (mol/s)
Mass / volume
What is a catalyst
A catalyst changes the rate of reaction (speeds it up) but is not used up- it is reusable and produces more of an energy-efficient chemical reaction.
What are enzymes
Biological catalysts within the body
How do catalysts work?
They provide a different reaction pathway where reactants do not require as much energy to react when they collide. They reduce the required activation energy.
In a word equation, what happens if the catalyst is used?
Nothing- it is not shown.
What are reversible reactions?
In some chemical reactions, the products can react again to reform the reactants.
How do you represent a reversible reaction?
A + B ⇌ C + D
What are the directions for a reversible reaction?
A + B Heat —-> C + D
Or
A + B Cool <—— C + D
If one direction of a reversible reaction is exothermic.. the opposite direction is?
Endothermic
State the four factors affecting rate of reaction
Temperature
Concentration
Surface area
Pressure (of gases)
How does temperature affect rate of reactions
The higher the temperature, the quicker the rate of reaction due to more collisions
How does concentration affect rates of reaction?
The higher the concentration the quicker the rate of reaction, there is more collisions within the chemicals.
How does surface area affect rates of reaction?
The larger the surface area of a reactant solid, the quicker the rate of reaction as there is more space for the particles to move and collide in.
How does pressure (of gases) affect the rates of reaction?
When gases react, the higher the pressure upon them, the quicker the rate of reaction.
