 Update your Table of Contents  Write your homework – leave it to be stamped  Get your test and your baby off the front counter if you want them!  Review Endothermic Vs. Exothermic DateSession # ActivityPage # 10/ /28 22 Rate of Reaction Note/Lab Guide 36 Study Guide for Chemistry Test 3 37

 6CO 2 + 6H 2 O + energy --> 6O 2 + C 6 H 12 O 6 ◦ Anybody know what this the chemical equation for? ◦ Photosynthesis  6O 2 + C 6 H 12 O 6 --> 6H 2 O + 6CO 2 + energy ◦ Anybody know what this the chemical equation for? ◦ Cellular Respiration

 The last few classes we focused on the Law of Conservation of Mass/Matter, or the idea of “What Goes In, Must Come Out,” BUT the Law of Conservation of Mass does not tell us anything about why a reaction occurs in the first place or the rate/speed at which they occur…

 With your group, brainstorm things that you think affect the rate, or speed, of a chemical reaction!

COLLISIONS BETWEEN MOLECULES ARE WHAT MAKE CHEMICAL REACTIONS OCCUR!

 Collisions are a factor in ALL reactions, but the other 5 factors below affect the speed/rate at which these collisions and therefore the reactions occur: ◦ Concentration ◦ Temperature ◦ Pressure ◦ Surface Area ◦ Catalysts

 Collision Theory – molecules bumping into each other lead to chemical reactions  How does this affect the Rate of Reaction? ◦ More collisions = more reactions ◦ Less collisions = less reactions

 Concentration – the amount or strength of the chemical  How does this affect the Rate of Reaction? Higher Concentration = more collisions = increased reaction rates Lower Concentration (dilute) = less collisions = decreased reaction rates

 Temperature – how hot/cold a substance is due to movement of particles ◦ What happens to particle movement when something is heated?  How does this affect the Rate of Reaction? Higher Temperature = more collisions = increased reaction rates Lower Temperature = less collisions = decreased reaction rates

 Pressure – a force on substances depending on the amount of space they have to move ◦ How do objects under pressure react? (Hint: think of open vs. closed container)  How does this affect the Rate of Reaction? Higher Pressure = more collisions = increased reaction rates Lower Pressure = less collisions = decreased reaction rates

 Surface Area – the area that an object occupies  How can you increase an objects surface area?  How does this affect the Rate of Reaction? Increased surface area = more collisions = increased reaction rates Decreased surface area = less collisions = decreased reaction rates

CHEMICAL REACTIONS NEED ENERGY TO OCCUR!

 Catalysts – a substance that acts as a “matchmaker” to jump start a reaction or make it faster (lowers the amount of energy needed)  Catalysts are not affected or used during the reaction – they are still left over Inhibitors are the opposite – how would you describe/define them?

 kP7A

 Group Leader – manages the group, reads the directions, makes sure everyone records data  Supply Manager – responsible for getting, returning and clean-up of supplies  Data Technician – Records your group’s data on the class data table on the board as soon as you have it!  Timekeeper – someone with a timer/stopwatch on their phone to time the reaction

 Send your supply manager to get 2 test tubes - some of you will receive solutions B1 & C and some of you will receive solutions B2 & C  Pour one of the solutions into the other and back again so all of the liquid is in one test tube…START YOUR TIMER IMMEDIATELY!  You must watch your experiment until you see the color change. If you are not paying attention, you will miss it!  Record the reaction times on your data table & decide as a group which factor affected the reaction rate!

 Send your supply manager to get your glue/water mixture, Borax and a popsicle stick.  Mix the Borax into the glue/water mixture and stir with the popsicle stick.  The borax DOES NOT BOND with the glue….it bonds the water with the glue, but is not part of the reaction….it is in the leftover liquid –  What role does the Borax play in this reaction?

Independent Variable What is Affecting the Reaction Rate? TemperatureTime for Reaction to Complete Powdered AlkaSeltzer Tablet N/A Broken AlkaSeltzer Tablet N/A Whole Alka Seltzer Tablet N/A Alka Seltzer in Hot Water HOT Alka Seltzer in Room Temp Water Room Temp Alka Seltzer in Cold Water COLD Alka-Seltzer in Film Canister 1 N/A Alka-Seltzer in Film Canister 2 N/A

 Complete the Study Guide  Review for Chemistry Test 3 next class!

 Update your Table of Contents  Write your homework – leave it to be stamped  Get your Study Guide out to be checked  Review with your Table Partners while I’m checking the homework DateSession # ActivityPage # 10/ /30 23 Testing Session (nothing to tape in)

HgO + Cl 2 HgCl + O 2

PbBr 2 +HClHBr + PbCl 2

Na 3 P + CaF 2 NaF + Ca 3 P 2

 Energy is a reactant  Temperature decreases, so it feels cool/cold  Example: Photosynthesis  Energy is a product  Temperature increases, so it feels warm/hot  Example: Cellular Respiration

 Collision Theory = all reactions take place due to collisions between molecules, but some things are able to increase or decrease the amount of collisions: ◦ Concentration = amount or strength ◦ Temperature = is due to particle movement ◦ Surface Area = break things into pieces to increase the surface area ◦ Pressure = the amount of space the particles have to move in (open vs. closed container) ◦ Catalyst = makes reactions go faster ◦ Inhibitor = makes reactions go slower

 Phone number:  Message: ◦ Text the number of your answer choice for multiple choice questions ◦ For open ended questions simply type your answer

 Please clear your desk of everything but your pencil and the blank periodic table I give you  Please put the folders up between you and your table partners.  WHEN YOU FINISH: ◦ Put your test in the basket and make a pile of unused periodic tables next to the basket ◦ Read the hand out on Energy, we will be attending a play next week