Energy Changes - CHEMISTRY Flashcards
What is a chemical reaction?
A process that involves the rearranging of ions or molecules to form a different substance
What are the signs of a chemical reaction?
-Temperature change
-Colour change
-Bubbles
-odour
Precipitate formation
In exothermic reactions the temperature of the reacting surroundings ……………….
Increase
In endothermic reactions the temperature of the reacting surroundings ………..
Decrease
What is the law of conservation of mass?
Mass is neither created nor destroyed by chemical reactions
Mass of products = mass of reactants
What is activation energy?
The minimum amount of energy required to start a reaction
Activation energy can be lowered by…
Heating the reactants
Using a catalyst
Making the reactants more concentrated
What are catalysts?
Something which speeds up a chemical reaction but remains chemically unchanged
How do catalysts work?
They provide an easier, alternative route for the reaction. This pathway has a lower activation energy than the original
Breaking bonds requires……
Energy
Bond forming ……. Energy
Releases
If a reaction is exothermic will there be more energy needed for bond making or bond breaking?
Bond making
