Heat changes in chemical reactions

  • 7,980 views
Uploaded on

 

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads

Views

Total Views
7,980
On Slideshare
0
From Embeds
0
Number of Embeds
6

Actions

Shares
Downloads
72
Comments
0
Likes
1

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. HEAT CHANGES IN CHEMICAL REACTIONS
  • 2.
    • The chemical reaction that results in heat produced is called an exothermic reaction.
    • Example- Dissolving sodium hydroxide in water.
  • 3.
    • Exothermic reaction accompanied by a rise in temperature of the surrounding.
  • 4.
    • The chemical reaction that absorbs heat from the surrounding is called an endothermic reaction .
    • Example- Dissolving ammonium chloride in water.
  • 5.
    • Endothermic reaction resulting a drop of the temperature of the surrounding.
  • 6.
    • Energy graph for an exothermic reaction
  • 7.
    • Energy graph for an endothermic reaction .
  • 8.
    • The change of energy level in a chemical reaction is denoted by the symbol
  • 9.
    • When the energy level of the product is higher than that of reactants , energy is absorbed.
    • The reaction is endothermic and
    • (+) ve.
  • 10.
    • When the energy level of the product is lower than the reactants, energy is released.
    • The reaction is exothermic and
    • (-) ve.
  • 11. HEAT CHANGES IN INDUSTRIAL CHEMICAL REACTION
    • If a reaction is exothermic and reversible, heating the process to a very high temperature would decrease the yield of the products.
    • Example- Production of ammonia
  • 12. HABER PROCESS
    • Production of ammonia
    • Nitrogen + Hydrogen Ammonia + Heat
    • Heat is given off. So a low temperature will give better yield.
    • But a low temperature will cause the reaction to proceed slowly.
    • A moderate temperature of 450-500 is used.
  • 13. CONTACT PROCESS
    • Production of sulphuric acid.
    • Sulphur dioxide + Oxygen Sulphurtrioxide + Heat
    • Heat is given off. So a low temperature will give better yield.
    • But a low temperature will cause the reaction to proceed slowly.
    • A moderate temperature of 400-500 is normally used.
  • 14.  
  • 15.
    • The sulphur trioxide is passed into concentrated sulphuric acid to form oleum.
    • Sulphur trioxide + Con. Sulphuric acid Oleum
    • Oleum + Water Sulphuric acid
  • 16. THE END