Energy from Reactions Flashcards
How can the relative amount of energy released when substances burn be measured?
Using a simple calorimetry
What does using a calorimetry mean?
Heating water in a glass or metal container
What does using a calorimetry allow you to compare?
The amount of energy released by food or fuels
What’s energy normally measured in?
J
Why may energy values be given in KJ?
For comparison
How can the amount of energy released or absorbed by a chemical reaction be calculated?
Measuring the temp. change of the solution when the reactants are mixed in an insulated container
What 2 reactions can measuring the temp. change be used to measure?
Solids with water
Neutralisation
What are simple energy level diagrams used to show?
The relative energies of reactants and products, the overall activation energy, and the overall energy change of a reaction
During a chemical reaction, energy must be supplied to…
Break bonds
During a chemical reaction, energy is released when…
Bonds are formed
What happens in terms of energy in an exothermic reaction?
The energy released from forming new bonds is greater than the energy needed to break existing bonds
What happens in terms of energy is an endothermic reaction?
The energy needed to break existing bonds is greater than the energy released from forming new bonds
Catalysts provide a different…
Pathway for a chemical reaction that has a lower activation energy
What can hydrogen be burned as a fuel in?
Combustion engines
Hydrogen + oxygen ->
Water
