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Exploring Chemical Reactions: Types and Energy Transfer

Learn about different types of chemical reactions, energy transfer, and how to identify reactions from formulas. Discover the roles of oxidation, combustion, and more in this interactive learning experience.

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Exploring Chemical Reactions: Types and Energy Transfer

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  1. CONCLUSION to the BLUE LAB!

  2. How do we know chemical reaction happened yesterday?

  3. How do we know chemical reaction happened yesterday? • major, unexplained, color change • major, unexplained temperature change • major, unexplained bubbles gas created • precipitate forms.

  4. Go over rest of sheet…

  5. What are some types of chemical reactions?

  6. We have already learned about 3 general types of chemical reactions:

  7. Which two below need oxygen? • OXIDATION reactions NEED O2as REACTANT

  8. Which two below need oxygen? • OXIDATION reactions NEED O2as REACTANT • combustion • corrosion

  9. What are the two ways heat &/or other energy can flow in & out of a reaction? • OXIDATION reactions NEED O2as REACTANT • combustion/fire • corrosion/rusting • E • E

  10. We have already learned about 3 general types of chemical reactions: • OXIDATION reactions NEED O2as REACTANT • combustion/fire • corrosion/rusting • EXOTHERMIC reactions RELEASE HEAT (or other energy)! • ENDOTHERMIC reactions ABSORB HEAT!

  11. Can you recognize which type of reaction it is just by its chemical reaction formula? HEATBa(OH)2+ 8 H2O + 2 NH4Cl → 2 NH3 + 10 H2O +BaCl2

  12. ENDOTHERMIC! This is the chemcial reaction for that cold pack. HEATBa(OH)2+ 8 H2O + 2 NH4Cl → 2 NH3 + 10 H2O +BaCl2

  13. ENDOTHERMIC! This is the chemcial reaction for that cold pack. HEAT+ Ba(OH)2 + 8 H2O + 2 NH4Cl → 2 NH3 + 10 H2O +BaCl2

  14. General types of chemical reactions: • OXIDATION reactions NEED O2as REACTANT • combustion/fire • corrosion/rusting • EXOTHERMIC reactions RELEASE HEAT (&/or other energy)! • ENDOTHERMIC reactions ABSORB HEAT (&/or other energy)!

  15. chemical reactions can fit more than one category…

  16. Can you recognize which type(s) of reaction it is just by its chemical reaction formula? 2 Cu + O2 2 CuO

  17. OXIDATION! See how oxygen is the reactant in how copper corrodes. 2 Cu + O2 2 CuO

  18. OXIDATION! See how oxygen is the reactant in how copper corrodes. 2 Cu + O2 2 CuO OXIDATION reactions are also EXOTHERMIC

  19. Chemical reactions can fit more than one category… • OXIDATION reactions NEED O2as reactant • combustion/fire • corrosion/rusting/tarnishing • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT!

  20. Can you recognize which type of reaction it is just by its chemical reaction formula?

  21. BOTH EXOTHERMIC & OXIDATION! THIS IS AN EXOTHERMIC COMBUSTION REACTION OF OCTANE IN YOUR CAR ENGINE!

  22. ALL OXIDATION reactions are all EXOTHERMIC! • OXIDATION reactions NEED O2as reactant • combustion/fire • corrosion/rusting/tarnishing • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT!

  23. YOU COMBUST…. YOU RUST…. YOU ARE EXOTHERMIC!

  24. What was yesterday’s reaction? 2 Cu + 4 HC2H3O2 Cu2(C2H3O2)4+ 2 H2

  25. It was EXOTHERMIC for SURE, but not with OXYGEN GAS as a reactant • OXIDATION reactions NEED O2as reactant • combustion/fire • corrosion/rusting/tarnishing • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT!

  26. THAT WAS THE OL’ SWITCHEROO! 2 Cu + 4 HC2H3O2 Cu2(C2H3O2)4+ 2 H2

  27. THERE’S A FEW MORE GENERAL TYPES OF CHEMICAL REACTIONS we should know. • OXIDATION reactions NEED O2as reactant • combustion • corrosion • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT! • REPLACMENT reactions

  28. THERE’S A COUPLE MORE GENERAL TYPES OF CHEMICAL REACTIONS we should know. • OXIDATION reactions NEED O2as reactant • combustion • corrosion • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT! • REPLACEMENT reactions-switcheroo!!

  29. Can you see why it’s called photoSYNTHESIS!??

  30. Can you see why it’s called photoSYNTHESIS!?? 12 small molecules here 1 BIGGER molecule

  31. Can you see why it’s called photoSYNTHESIS! phytoplankton & plants take 6 small molecules of carbon dioxide & water and turn it into 1 BIG glucose!

  32. THERE’S A FEW MORE GENERAL TYPES OF CHEMICAL REACTIONS we should know. • OXIDATION reactions NEED O2as reactant • combustion • corrosion • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT! • REPLACEMENT reactions—switcheroo!! • SYNTHESIS reactions BUILDS things UP

  33. THERE’S A FEW MORE GENERAL TYPES OF CHEMICAL REACTIONS we should know. • OXIDATION reactions NEED O2as reactant • combustion • corrosion • EXOTHERMIC reactions RELEASE HEAT! • ENDOTHERMIC reactions ABSORB HEAT! • REPLACEMENT reactions—switcheroo!! • SYNTHESIS reactions BUILDS things UP! • DECOMPOSITION reactions BREAKS DOWN

  34. LET’S DO A DECOMPOSITION REACTION!! • LET’S BREAK DOWN HYDROGEN PEROXIDE!

  35. How can we SPEED a reaction up? • This can take months…most decomposition reactions do.

  36. How can we SPEED areaction up? • ADD A CATALYST (substance that speeds up a reaction WITHOUT getting involved) • chlorophyll in photosynthesis • salt for water electrolysis • sulfuric acid for oxidizing sugar

  37. Catalysts are substances that speed reactions up without changing themselves… • Like a baby walker helps a newborn walk… • …BUT is unchanged.

  38. Catalysts are substances that speed reactions up without changing themselves… • Like slippery OIL helps the engine run faster… • …BUT is unchanged.

  39. How can we SPEED the reaction up? • ADD A CATALYST (substance that SPEEDS up a reaction WITHOUT getting involved) • chlorophyll in photosynthesis • salt for water electrolysis • sulfuric acid for oxidizing sugar • H2O2 for speeding up our blue lab

  40. WHAT’S HAPPENING HERE? IRON (Fe) RUSTS (CORRODES) IN WATER BUT THE RUST REACTION IS: 4 Fe + 3 O2 2 Fe2O3

  41. WHAT’S HAPPENING HERE? IRON (Fe) RUSTS (CORRODES) IN WATER BUT THE REACTION IS AN OXIDATION REACTION AND HAS NO WATER IN IT: 4 Fe + 3 O2 2 Fe2O3 WHY DO WE CONNECT (ASSOCIATE) WATER (H2O) WITH RUSTING WHEN IT ISN’T EVEN A REACTANT?

  42. REMEMBER OUR WATER QUALITY INDICATORS? N,T or P then DO

  43. DISSOLVED OXYGEN (DO) DEFINITION: • the amount oxygen GAS (O2) bubbles dissolved in the water

  44. GOOD DO CAUSES: MORE DISSOLVED OXYGEN LESS DISSOLVED OXYGEN • turbulence (waves, rapids), • REGULAR phytoplankton algae & plant growth (photosynthesis releases O2 in water) GOOD for the water!!!

  45. LOW DO CAUSES: LESS DISSOLVED OXYGEN • higher temperatures(More O2 escapes, possibly from high turbidity or power plants!) • High nitrate levels/when algae blooms die & decomposers poop! BAD for water!!

  46. Dissolved Oxygen RESULTS: • When dissolved oxygen drops too low, FISH CAN’T BREATHE what little oxygen is there! • Look for contributing causes! • thermal pollution (T to high) • too much nitrates • high turbidity

  47. WATER IS A CATALYST IN RUSTING! IRON (Fe) RUSTS (CORRODES) IN WATER BUT THE REACTION IS AN OXIDATION REACTION AND HAS NO WATER IN IT: H2O 4 Fe + 3 O2 2 Fe2O3 WATER (H2O) SPEEDS UP RUSTING/CORROSION BY HOLDING OXYGEN GAS ONTO THE STEEL.

  48. How can we SPEED the reaction up? • ADD A CATALYST (substance that speeds up a reaction but IT DOESN’T CHANGE) • chlorophyll in photosynthesis • water holds O2 onto steel to speed up oxidation

  49. Molecules move faster when heated. The hotter it is, the quicker it COOKS.

  50. How can we SPEED the reaction up? • ADD A CATALYST (substance that speeds up a reaction without getting involved) • chlorophyll in photosynthesis • water holds O2 onto steel to speed up oxidation • INCREASE TEMPERATURE (speeds up the molecules to react faster) • warming up our potassium permanganate & glycerin reaction

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