energy changes 5 Flashcards
what happens to energy in a reaction
energy is conserved in reactions and only move around
what is an exothermic reaction
one that transfers energy to the surroundings usually by heating
examples of exothermic reactions
combustion
neutralisation reactions
oxidation reactions
what is an endothermic reaction
one that takes in energy from the surroundings
examples of endothermic reactions
thermal decomposition
reaction between citric acid and sodium hydrogencarbonate
everyday uses of endothermic reactions
sports injury packs (allow the pack to become instantly cooler)
everyday uses of exothermic reactions
hand warmers(oxidation of iron in air to release energy) self heating cans(chemicals in there base)
what happens to bonds during a reaction
old bonds break and new ones form
what reaction is bond breaking
endothermic
what reaction is bond forming
exothermic
what reaction has a minus in bond calculations
exothermic
what reaction has plus in bond calculations
endothermic
what are reaction profiles
diagrams that show the relative energies of the reactants and products in a reaction
what is the activation energy
the initial rise. and is the minimum amount of energy the reactants need to collide with each other and react.
what does the difference in height mean in reaction profiles
represents the overall energy change in the reaction