1. Objective: Identify and describe factors that influence reaction rates. Warm-up: Why do we keep food in the refrigerator?

2. How Can You Speed Up or Slow Down a Reaction ?

4. Experiment 1: The Effect of Temperature on Reaction Rates Reaction Times at Different Temperatures Hot Water Room Temp. Cold Water ________ C _________ C _________ C 1200 1150 1100 1050 1000 950 900 850 800 750 700 650 600 550 500 450 400 350 300 250 200 150 100 50 0

5. Experiment 1: The Effect of Temperature on Reaction Rates Summary: As the temperature increases, the rate of reaction… Questions: 1. At a temperature of 10 degrees C, it would take ______ seconds for 1 Alka-Seltzer tablet to react with 8 oz. of water. 2. If the temperature is doubled from 20 degrees C to 40 degrees C, the time for the rate of reaction ______by approximately _______. 3. Using hot tap water, the rate was ______ times faster than at 0 degrees C. increases

6. Experiment 2: The Effect of Particle Size on Rate of Reaction Particle Size Time for Reaction to be Completed Whole Tablet _________ Seconds 8 Pieces _________Seconds Powder _________Seconds

7. Experiment 2: The Effect of Particle Size on Rate of Reaction Summary: a) As particle size decreases, the rate of reaction ___________. b) The rate of reaction for the powder was ___________ times faster than for the whole tablet. Questions: 1. As particle size decreases, the total surface area of a reactant ________________. As a result, the probability of interactions between atoms/ions ________________, and the rate of reaction ___________________. 2. Particle size appears to have _______________ (less or more) of an effect on the rate of reaction than temperature. increases less