Energy changes Flashcards
What is an exothermic reaction?
A reaction that transfers energy to its surroundings. Products have less energy than reactants. Released energy reaction eg. neautrilisation reactions
What are the uses of exothermic reactions?
Hand warmers - exothermic reaction of oxidation iron (salt solution catalyst) to produce heat
Self-heating cans of hot chocolate/coffee rely on exothermic reaction of chemicals in their bases.
Glow stick - releases light energy
What is an endothermic reaction?
A reaction that takes energy from the surroundings, products have more energy than reactants. Eg. thermal decomposition reactions
Uses for endothermic reactions
Sports injury packs that take energy from heat and become cold - more efficient than ice.
What is a reaction profile?
A graph which shows energy change in reaction as it progresses. Starts at energy level of reactants and finishes at energy level of products.
What is overall energy change?
The difference between energy of reactants and energy of products.
How to find activation energy in a reaction profile?
From reactant energy to highest point of the curve.
Why is there a change in energy when a reaction happenes?
Because energy is taken in to break new bonds (endothermic) and energy is released to form bonds (exothermic)
How to calculate overall energy in bonds?
