C3 - Energy Calculations Flashcards
How is energy release calculated?
mass of water heated x specific heat capacity of water x rise in temp.
What is the formula for energy release in a reaction?
Q = mcΔT
Why is a polystyrene cup a good calorimeter?
It is an insulator so prevents energy loss through the sides.
What types of reactions can energy transfer be calculated for using a thermometer?
Neutralisation and Displacement
What can energy level diagrams show?
The relative difference in the energy of reactants and products.
What effect do catalysts have on the activation energy of a reaction?
Catalysts lower the activation energy.
What type of reaction is bond breaking?
Endothermic
What type of reaction is bond making?
Exothermic
What type of energy transfer has occurred is the products have more energy than the reactants?
Endothermic
What is bond energy?
The energy needed to break the bond between two atoms.
What is needed to calculate the energy change for a chemical reaction?
- How much energy is needed to break the chemical bonds in the reactants.
- How much energy is released when the new bonds are formed in the products.
What makes a reaction exothermic?
If the energy released when new bonds are formed is less than the energy absorbed when bonds are broken.
What makes a reaction endothermic?
If the energy released when new bonds are formed is less than the energy absorbed when bonds are broken.
Give two main problems of using fossil fuels.
- Carbon dioxide contributes to global warming,
- They are non-renewable.
What is produced when hydrogen burns?
Water
