Endothermic means taking in heat/energy (reactant product
+ energy) melting, boiling, evaporating
Exothermic means giving off heat/energy (reactant + energy
product) combustion
Thermal decomposition- breaking don of substances using heat
Collision theory- chemical reaction can occur only when reacting particles collide with each other
and sufficient energy. The minimum amount of energy that particles must have to react is called
activation energy.
Things that affect the speed of reaction:
Temperature
Concentration
Pressure
Surface area
Catalyst increase the rate of reaction by providing a different pathway for the reaction that has
lower activation energy.
There is always a balance between the energy needed to break bonds and the energy released when
new bonds are made. This energy release is what determines whether a reaction is exothermic or
endothermic. Bond energy is measured in KJ/mol. We can use bond energy to calculate energy
change for many reactions. The energy released when a bond is formed or absorbed when it is
broken is called the bond energy.
Covalent: non-metal + non- metal
Ionic: metal + non-metal
Metallic: metal + metal
C-C: single bond
O=O: double bond
N=N: triple bond
Exothermic- the energy need to break the bonds is less than the energy released when new bond are
made
Place the polystyrene cup inside the glass beaker to make it more stable. Measure an appropriate
volume of each liquid, e.g. 25cm3. Place one of the liquids in a polystyrene cup. Record the
temperature of the solution. Add the second solution and record the highest or lowest temperature
obtained. Change your independent variable and repeat the experiment. Your independent variable
could be the concentration of one of the reactants, or the type of acid/alkali being used, or the type
of metal/metal carbonate being used.
+ energy) melting, boiling, evaporating
Exothermic means giving off heat/energy (reactant + energy
product) combustion
Thermal decomposition- breaking don of substances using heat
Collision theory- chemical reaction can occur only when reacting particles collide with each other
and sufficient energy. The minimum amount of energy that particles must have to react is called
activation energy.
Things that affect the speed of reaction:
Temperature
Concentration
Pressure
Surface area
Catalyst increase the rate of reaction by providing a different pathway for the reaction that has
lower activation energy.
There is always a balance between the energy needed to break bonds and the energy released when
new bonds are made. This energy release is what determines whether a reaction is exothermic or
endothermic. Bond energy is measured in KJ/mol. We can use bond energy to calculate energy
change for many reactions. The energy released when a bond is formed or absorbed when it is
broken is called the bond energy.
Covalent: non-metal + non- metal
Ionic: metal + non-metal
Metallic: metal + metal
C-C: single bond
O=O: double bond
N=N: triple bond
Exothermic- the energy need to break the bonds is less than the energy released when new bond are
made
Place the polystyrene cup inside the glass beaker to make it more stable. Measure an appropriate
volume of each liquid, e.g. 25cm3. Place one of the liquids in a polystyrene cup. Record the
temperature of the solution. Add the second solution and record the highest or lowest temperature
obtained. Change your independent variable and repeat the experiment. Your independent variable
could be the concentration of one of the reactants, or the type of acid/alkali being used, or the type
of metal/metal carbonate being used.
