Energy and chemical reactions

1
Energy and chemical reactions

• Chapter 2
• Section 2-4 pg. 49-53

2
Energy

• Energy the ability to do work or cause change
• Examples light, thermal (heat), mechanical,
  chemical, electrical,
• Energy can be converted into different forms but
  can NEVER be destroyed
• Ex. We convert chemical? mechanical

3
Chemical Reactions

• Adding or taking away energy changes the state?
  and leads to a chemical reaction
• CO2 H20 ? H2CO3
• Reactants CO2 and H20
• Products H2CO3
• Reactants are found on the left side of the arrow
• Products are on the right side.
• Reactions must be balanced (have the same number
  of each type of atom on both sides)
• Two direction arrows, mean the reaction can go
  backward and forward. ??
• Reactants Products
• 6CO2 6H2O light C6H12O6 O2

4
Activation Energy

• Activation Energy- energy needed to start a
  reaction (usually high)
• Catalysts substances (enzymes) that reduce the
  amount of activation energy needed to start a
  reaction
• Catalysts in living organisms are called enzymes

5
Energy Transfer

• Your body continuously undergoes a series of
  chemical reactions
• There are 2 types of reactions
• Exergonic reactions- net RELEASE of Energy
• 2. Endergonic Reactions- net ABSORPTION of energy
  (most rxns in cells)
• We need a constant supply of energy to make
  energy
• This is why we need to keep eating food? we
  need to take in E to make E to use.