Chemistry (Chapter 12)- Energy changes in chemical reactions
-Positive enthalpy change
-Bonds are broken
-Negative enthalpy change
-Bonds are made
When are endothermic reaction used in everyday objects
Cold packs for sports injuries.
Ammonium nitrate dissolves, energy is absorbed making the surroundings cooler
When are exothermic reaction used in everyday objects
-Hand warmers, self heating cans
-Calcium oxide is added to water, releasing heat energy
When food and fuels react with oxygen...
What is released in what type of reaction?
What unit of measurement is used?
What piece of equipment can we use?
Draw and describe an endothermic energy level diagram
-Energy is absorbed by the reaction, temp drops.
-Products have higher energy levels (thus +entalaphy change)
Draw and describe an exothermic energy level diagram
-Energy is released, temp rises
-Products have lower energy levels (thus -entalaphy change)
What affects does a catalyst have on the structure of the graph
-The height of graph will be lower if catalyst is present
-Due to lower activation energy
In chemical reactions, energy must be supplied to _____________ between atoms in the reactants
break the bonds
When new bonds are formed....
energy is released
In an exothermic reaction, the energy released when new bonds formed is_________ than when bonds are broken
In an endothermic reaction, the energy released when new bonds formed is_________ than when bonds are broken