C3.3 Flashcards
What can be measured by simple calorimetry
The relative amounts of energy released when substances burn
What two things can simple calorimetry be used for
Heating water in a glass or metal container
To compare the amount of energy released by fuels and foods
What is energy measured in
Joules
Where can the amount of energy released or absorbed by a chemical reaction in a solution be calculated from
The measured temperature change of the solution when the reagents are mixed in an insulated container
What method can be used for reactions of solids with water or for neutralisation reactions
Measuring the temperature change of the solution where the reagents are mixed in an insulated container.
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
What two things happens during a chemical reaction
Energy must be supplied to break bonds
Energy is released when bonds are formed
What is an exothermic reaction
The energy released from forming new bonds is greater than the energy needed to break existing bonds
What is an endothermic reaction
The energy needed to break existing bonds is greater than the energy released from forming new bonds
What do catalyst provide
A different pathway for a chemical reaction that has a lower activation energy
What can 3 things can hydrogen be used for
When burnt, as a fuel in a combustion engines
In fuel cells that produce electricity to power vehicles
Hydrogen + oxygen =
Water