Week 1 Flashcards
What is an exothermic reaction ?
An exothermic reaction is one that transfers energy to the surroundings
What is an endothermic reaction?
An endothermic reaction is one that takes in energy from the surroundings
What happens to the temperature of the surroundings during an exothermic reaction?
The temperature of the surroundings increases (because energy has transferred to the surroundings)
What happens to the temperature of the surroundings during an endothermic reaction?
The temperature of the surroundings decreases (because energy is taken in from the surroundings)
What are some examples of exothermic reactions?
Combustion and neutralization
What are some uses of exothermic reactions?
Hand warmers
What are some examples of endothermic reactions?
Thermal decomposition (heating something up until it breaks down)
What is a use of endothermic reactions?
Ice packs
Draw the reaction profile for an endothermic reaction
- the reactants should be below the products
- there should be an upwards arrow from the reactants to the Peak of the curve labeled activation energy
- there should be a upwards arrow from the reactions to the products labeled energy change
Draw the reaction profile for an exothermic reaction
-The reactant should be above the products
- that should be a downward arrow from the reactants to the product labeled energy change
- there should be an upward arrow from the reactants to the peak of the curve labeled activation energy
How do you work out the energy change of a reaction?
- Work out how many of each bond there are
- Add up the bond energies of all the reactants
- Add up the bond energies of all the products
- Energy of products - energy of reactants
What is the energy change for an exothermic reaction?
The energy change is negative as energy is lost when it is transferred to the surroundings
What is the energy change for an endothermic reaction ?
The energy change is positive as energy is taken in from the surroundings
