topic 8 – reaction rate · when oxygen in air reacts with metal. ex. rust. 4 fe (s) + 3 o. 2(g) 2...
TRANSCRIPT
Topic 8 – Reaction Rate
Science 9 - Chemistry
Learning Target
1. Describe combustion, corrosion and other reactions involving oxygen
Chemical Reactions involving oxygen
1. COMBUSTION - oxygen reacts with a fuel source to produce water vapor, carbon dioxide gas and heat energy
Ex. Fire, explosion
What products are produced in combustion?
CH4(g) + 2 O2(g) CO2(g)+ 2 H2O (g)
Methane + oxygen carbon dioxide + water
2. CORROSION – slow chemical change when oxygen in air reacts with metalEx. Rust
4 Fe(s) + 3 O2(g) 2 Fe2O3(s)Iron + oxygen iron oxide
How do we protect against rust?
Galvanizing – Coating metals with thin layers of zinc– Zinc takes longer to rust than most metals!
Painting Sacrificial metal
PBS Nova – Smart Bridges
https://www.youtube.com/watch?v=8qcREJ2NsOQ (SmartBridge) https://www.youtube.com/watch?v=yVQn1D
YmiXE (War on Corrosion)
3. CELLULAR RESPIRATION – chemical reaction that takes place in your body cells.C6H12O6 + O2 CO2 + H2O + energy
Learning Target
Identify conditions that affect the rates of reactions.
Factors Affecting Rates of Chemical Reactions
REACTION RATE – the speed at which reactants are converted to products during a chemical reaction.
Factors Affecting Rates of Chemical Reactions
Many factors can affect chemical reactions– How can you make water boil faster?
1. Changing Temperature • Temp = reaction rate • Temp = reaction rate
2. Stirring the Reactants Adding movement energy and speed of
atoms / molecules = collisions between atoms = reaction rate
3. Increasing Surface Area surface area = reaction rate
Catalysts4. Catalysts – A substance that RR without being changed itselfEx. Enzyme (natural catalyst) – made by living things
Enzymes in the human body https://www.youtube.com/watch?v=myORDWVzNhc
5. Changing Concentrations – number of particles (atoms or molecules) per unit of volume changes reaction rate
# of particles / unit of volume = RR# of particles / unit of volume = RR
X mol/L acetic acid (aq)vs.
.8 mol/L acetic acid (aq)
Bozeman science https://www.youtube.com/watch?v=6mAqX31RRJU Ted-Ed
https://www.youtube.com/watch?v=OttRV5ykP7A