icp 11/26/12 reaction rates chemical reactions unit review reaction rates prelab

ICP

11/26/12Reaction Rates

Chemical Reactions Unit ReviewReaction Rates Prelab

Warmup

• List five things that affect reaction rate. (See your flowchart from last week.)

Agenda

• Reaction Rates• Reaction Rates prelab• Chemical Reactions Unit Review

Reaction Rates

Chemical reactions can be sped up or slowed down depending on several factors:

1) Temperature2) Surface Area3) Stirring4) Concentration5) Catalysts

Temperature

• Affects reaction rate by: Hotter temperatures cause a reaction to go faster. Colder temperatures cause a reaction to go slower.

• Causes particles to: This is because higher temperature means that particles are moving faster and are colliding to react more often.

Surface Area

• Affects reaction rate by: A chemical with more surface area will react faster than a chemical with less surface area.

• Causes particles to: Reactions can only occur at the surface of a chemical, so the more surface area, the more chance for the chemical to interact with other chemicals. Think about how rock salt dissolves slower than granular salt. The rock salt has less surface area per weight.

Stirring

• Affects reaction rate by: Stirring makes a reaction go faster.

• Causes particles to: This causes particles to move around more and interact more often.

Concentration

• Affects reaction rate by: A higher concentration of chemical will react faster than a lower concentration.

• Causes particles to: This is because a higher concentration offers more reactive particles closer to each other so that they are more free to react.

Catalyst

• Affects reaction rate by: A catalyst is a bystander chemical that instigates (makes a reaction go faster without actually being used up in the reaction).

• Causes particles to: A catalyst allows particles to collide together in a way more likely to break bonds.