Calculating and explaining energy change Flashcards
Relative amounts of energy released when substances burn can be measured using what?
A simple caliormeter.
Specific heat capacity equation:
Q = m x c x theta
Where: Q is energy in J m is mass in kg c is specific heat capacity in J/kgC theta is temperature change
Energy is usually measured in what unit?
Joules, J.
The amount of energy released or absorbed in a reaction can be calculated how?
By measuring the temperature change of the solution when reagents are mixed in an insulated container.
Measuring temperature change in an insulated container works for what types of reactions?
Reactions of solids with water and neutralisation reactions.
What can be used to show reactant energies of reactants and products, the activation energy and the overall energy change in a reaction?
Simple energy level diagrams.
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.
Catalysts provide what that lower the activation energy?
A different pathway for the reaction to take place.
True or false, hydrogen can be used as a fuel in combustion engines.
True.
Equation for the combustion of hydrogen:
Hydrogen + Oxygen = Water
