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Key Question: What is the difference between exothermic and endothermic reactions. Warm-up: Name 2 ways you could speed up a chemical reaction.

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Presentation on theme: "Key Question: What is the difference between exothermic and endothermic reactions. Warm-up: Name 2 ways you could speed up a chemical reaction."— Presentation transcript:

1 Key Question: What is the difference between exothermic and endothermic reactions. Warm-up: Name 2 ways you could speed up a chemical reaction.

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

3 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.

4 Demo Labs! Yeast & Peroxide Lab Epson Salt Lab

5 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.

6 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.

7 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.

8 8 What is this?

9 9 Look at the ingredients!

10 10 This is an exothermic reaction. Rusting metal releases heat energy. In a Hot Hands warmer the water and salt make the tiny iron particles rust so fast they heat up quickly. This is a chemical change because we get energy and a new substance iron oxide or rust. In this reaction the atoms of iron and oxygen bond together to make the rust. To prevent rust iron surfaces must be painted to keep the oxygen off the atoms of iron. Water and salt helps to loosen iron atoms from the metal so that oxygen in the air can more easily bond to them.

11 At outdoor school you will notice the orange mud in the wetlands. This is caused by iron in the soil that rusts when exposed to oxygen in the water and the air.

12 During what season of the year would a car rust the most? What made the iron rust faster? ( (

13 Wet snow & salt that is spread on the roads makes rusting happen faster.

14 So what can speed up the rusting process?? Catalyst : speeds up a chemical reaction Example: water & salt act as catalysts for rusting Inhibitor : slows down or delays a chemical reaction. Example: paint is a rust inhibitor. Activation Energy : the minimum energy needed to start a chemical reaction VOCABULARY: Blue parts in 3 rd box

15 Complete the worksheet “Overview: Chemical Reactions” (both sides) INDEPENDENTLY!! Wordsearch is LAST.


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