Key Question: What is the difference between exothermic and endothermic reactions. Warm-up: An increase in temperature makes a reaction ____________. (speed up or slow down) A larger particle size makes a reaction _____________. (Speed up or Slow down) speed up slow down

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

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

**Experiment 4: Effect of Mechanical Mixing Will the reaction rate be faster when - I just drop baking soda into vinegar OR when - I stir the baking soda into vinegar?

Let’s Review What Can Change Chemical Reaction Rates. Temperature - Particle Size - Mixing - temperature,reaction rate particle size,reaction rate Mixing, reaction rate

Would a glow stick last longer if I put it in hot water or cold water? WHY?

HOMEWORK: Answer the following question: Which would react more quickly in a chemical reaction…. a sugar cube or an equal mass of sugar crystals. Explain your answer.

Think about the 5 indicators Temperature change & light produced are both the result of a change in ______________. energy

Exothermic and Endothermic Reactions Exothermic reaction - a reaction that releases energy. The reactants have more energy than the products. Energy must be released as the products form. The container in which an exothermic reaction is taking place will feel warm Endothermic reaction - a reaction that absorbs energy. The products have more energy than the reactants. Energy must be absorbed as the products form. The container in which an endothermic reaction is taking place will feel cold Copy the parts in RED into your vocabulary page.

Demo Labs! Yeast & Peroxide Lab Epson Salt Lab

Yeast & Peroxide Lab Analysis and Conclusions 1. Was this a chemical or physical reaction? Explain your answer. 2. Why did the temperature change? 3. Based on your data explain why you think this was an endothermic or exothermic reaction. 4. Give at least one other example of an exothermic reaction you are familiar with. How do you know it is exothermic? The formation of gas released energy/heat. Chemical reaction because a gas was produced and there was a change in temperature. Exothermic, the temperature went up which means energy was being released during the reaction.

Epsom salt Lab Analysis and Conclusions: 1. What is the amount of temperature difference of the water before and after adding Epsom salt? 2. Why did the temperature of the water change? There was a _________ change in temperature. Because the product being made was absorbing energy.

Epsom salt Lab 3. Was this an endothermic or exothermic reaction? Explain your answer. 4. Does mixing Epsom salts and water indicate a physical or chemical change? SUPPORT YOUR CONCLUSIONS WITH EVIDENCE FROM YOUR EXPERIMENT Endothermic, the temperature of the water dropped which means energy was being used up in the reaction.