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2 How Substances Dissolve 1. Cluster together 2. Water pulls the salt into the solution 3. Spreads out to form Homogenous Solution
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5 Factors Affecting Reaction Rates Most reactions go faster at higher temperatures Due to kinetic energy-hotter leads to faster particles Faster particles lead to higher energy which leads to more collisions Example –potato slices cook faster at than 100 0
6 Larger surface area speeds up reactions More exposed area the faster the reaction Example – whole potato will take 30 minutes to cook Same potato sliced will take 10 minutes Solids-powder will dissolve quicker in solution than large block of material Sugar cube vs sugar granules
7 Concentrated (stronger) solutions react faster Small amount of solution will not be effective Bleach Large amount of solution will be effective
8 Reactions are quicker at higher pressure -Higher pressure - more particles in lead to more collisions Quicker reactions -Lower pressure - less particles lead to less collisions -Slower reactions -Example – shake up a bottle of soda- increase collisions which increase explosion when opened
9 Massive, bulky molecules react slower The larger the molecule the slower it is Some molecules need to collide on particular side for reaction to happen This takes many tries before large molecules react Result – compounds react very slowly
10 Catalysts Changes the rate of chemical reactions without being consumed Speeds up or slows down reactions Inhibitor-catalysts that slow reactions Food Preservatives Solid catalyst- usually speeds up reactions Catalytic converter on car More effective with large surface
11 Equilibrium Systems The balance between a chemical reaction and its reverse occurring simultaneously Carbonated drink in closed container Burning, rusting and explosions are completed reactions Can’t be reversed
12 La Chatelier’s prinicple of equilibrium A change in chemical equilibrium leads to an equilibrium shift to a new equilibrium Change is caused by Temperature – Pressure – Concentration-