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Chemistry 2020 CT2 (Heat Energy Changes in Chemical Reactions (Exothermic…
Chemistry 2020 CT2
Heat Energy Changes in Chemical Reactions
Exothermic Reaction
Temperature of surroundings increases
energy is released from the reaction to the surroundings
Can be used for hand warmers
Makes bonds
Endothermic Reaction
Temperature of the surroundings decreases
energy is transferred from the surroundings to the reaction
Can be used for ice packs (Sports injuries)
Breaks bonds
Activation energy is the minimum amount of energy needed to start a reaction
Groups in the Periodic Table
Group 7
Diatomic Molecules
React with metals to form salts.
Halogens
Uses
Disinfecting Water
Bleaching
Reactivity goes up as you go up the group
Group 0
Obtaining & Using Metals
Corrosion
Corrosion of iron and steel requires water and oxygen
Another word used is rusting
When a metal becomes weaker because of a reaction with water and oxygen
Metals react with water to create metal hydroxide and hydrogen
Life Cycle Assessment
Positives of Recycling
No Landfill
Uses less energy than extracting from the ore
Negatives of Recycling
Destroys animals habitats
Releases Co2 into the atmosphere
Balancing Equations
Magnesium + Oxygen -----> Magnesium Oxide
Mg + O2 ------> MgO
2
Mg + O2 ---->
2
MgO