Topic 8 – Reaction Rates
Reaction Rate
•
A _______________________________ is a measure of how fast a reaction occurs
– To measure:
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Find out how quickly one of the reactants is disappearing OR
•
Find out how quickly one of the products is appearing.
Can the Reaction Rate be changed?
•
1. _____________________________________________________
•
2. _____________________________________________________
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3. Adding a Catalyst
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4. Inhibitors
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5. ______________________________________________________
Inhibitors
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_________________________ are substances that ______________________________ down
chemical reactions.
– Inhibitors are added to some foods and medicines to slow down their
decomposition.
Catalysts
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A ____________________ is a substance that _________________________ up the rate of a
reaction without being changed itself.
Enzymes
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An ____________________________________ is a NATURAL catalyst made by living things.
– Example:
•
When you chew up that delicious sandwich, glands in your mouth
produce saliva which contains _________________________________ to break
down food.
–
The enzyme in saliva works as a catalyst to break down food.
Temperature
•
The rate of a chemical reaction can be sped up or slowed down by changing the
_________________________________________
– At _____________________________ temperatures, reactions will increase in speed
– At _____________________________ temperatures, reactions will decrease in speed
Stirring
•
_______________________________________ a mixture will usually make a reaction
happen more quickly
– Think about salt dissolving in water, if you stir it, the salt will dissolve MUCH quicker
Corrosion
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When metals are exposed to air and moisture, what happens???
– ______________________________________
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_____________________________ is the oxidation of metals or rocks in the presence of air
and moisture
– __________________________ is an example of corrosion (rust is called iron (II) oxide
trihydrate)
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Rust -> Iron + Oxygen + Moisture
Poor Metals….
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Corroded materials lose their strength  Pooooor metals…. 
– Things like rust will eventually make its way through the metal and it will all
corrode away….
•
•
NO more metals…… 
HOW DO WE SAVE THE METALS FROM THEIR DEMISE?!?!
Preventing Corrosion
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1. Apply a thin coat of paint.
•
2. Coat the metal with zinc (way more resistant to corrosion)
•
Coating metals with a thin layer of ___________________________ is called
___________________________________________
– Who can think of some metals that are galvanized?