C3.3 Calculating and explaining energy change Flashcards
What is energy measured in?
Joules
How can the amount of energy released / absorbed from a chemical reaction be calculated?
From the measured temperature change of the solution when they are mixed in an insulated container. This method can be used for reactions of solids with water or for neutralisation reactions
What can simple energy level diagrams be used to show?
The relative energies of reactants and products, the 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
In an exothermic reaction, the energy released from forming new bonds is…
Greater than the energy needed to break the existing bonds
In an endothermic reaction, the energy needed to break the existing bonds is…
Greater than the energy released from forming new bonds
What do catalysts provide?
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
What else can hydrogen be used in?
Fuel cells that produce electricity to power vehicles
