Chemistry Packet #2 Reg.
Ms. Rabenda
Name: __________________________Per: ___
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Endothermic and Exothermic
Reaction Notes
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Chemical Reactions
• Indicators of Chemical Reactions
• ________________________
• Odor Change
• Gas produced → New substance not just boiling
• Bubbles produced → Must be a new gas and not just boiling
• Gives off a precipitate
• Temperature change
• ______________ / ________________
Temperature Changes
• 2 Different Types
• Endothermic
• Endo = ____________
• Therm = Temp
• Heat taken In; Reaction becomes warmer but surrounding
temperature drops
• Exothermic
• Exo = _________ /_________
• Therm = Temp
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Heat released; Reaction loses heat but surrounding temperature rises
Endothermic
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Exothermic
A reaction that ________/_________ in heat
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A reaction that _______________ heat
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More energy is supplied than released
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More energy is released than supplied
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Temperature _______________
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Temperature _________________
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Occurs when the bonds between atoms break
(energy is absorbed)
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Occurs when atoms bond together (energy
is released)
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Examples:
• Photosynthesis
• Melting Ice Cubes
• Evaporation of water
• Baking Bread
• Cooking an Egg
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Example:
• Burning fossil fuels
• A candle flame
• Iron Rusting
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Exothermic and Endothermic
Reaction Worksheet
All chemical reactions involve energy. Exothermic reactions are chemical reactions in which energy is
released. Endothermic reactions are chemical reactions in which energy is absorbed.
1. A chemical reaction in which energy is absorbed is called
a. endothermic reaction.
b. oxidation reaction.
c. activation reaction.
d. exothermic reaction.
2. A chemical reaction in which energy is released is called an
a. endothermic reaction.
b. oxidation reaction.
c. activation reaction.
d. exothermic reaction.
Write EX if the reaction is exothermic. Write EN if the reaction is endothermic.
3. __________ A cake bakes
4. __________ Oil is burned
5. __________ Fireworks explode
6. __________ When two chemicals mix their temperature rises
7. __________ A solid burns brightly and releases heat, light and sound
8. __________ When two chemicals are mixed their temperature drops
9. __________ Two chemicals will only react if you heat them continually
10. __________ Plants take in light energy for photosynthesis
11. __________ Clay turns into brick when it is heated in a kiln at high temperatures
12. __________ Dead plant material decays, producing warm compost
13. __________ Logs burning in a fireplace
14. _________ Electricity being used to change water into hydrogen and oxygen gas
15. _________ Gasoline burning in an automobile engine
16. _________ Plants using sunlight, carbon dioxide, and water to make sugar and oxygen
17. _________ The explosion of dynamite
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Endothermic /
Exothermic Lab - Part 1
Hypothesis:
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If I combine baking soda and vinegar then the temperature of the vinegar will _____________.
Materials - Part 1 - Endothermic
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Plastic Bag
Graduated Cylinder
Thermometer
Baking soda
Plastic Cup
Vinegar
Procedure - Part 1 - Endothermic
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Pour 20 mL of vinegar into an empty plastic bag.
Feel the bag. Observe and record how the temperature feels in the data table below.
Place the thermometer in the bag. Make sure the bulb of the thermometer is in the solution.
Record the temperature of the vinegar below. Leave the thermometer in the bag.
Measure 5 g of baking soda using the scale
Carefully pour the baking soda into the bag and gently mix. (Be careful—the chemical reaction will cause foam
to fill the bag.)
7. Wait 30 seconds and record the temperature again.
8. Remove the thermometer from the bag and carefully zip the bag.
9. Feel the bag again and note how the temperature change feels. Record your observations below
Data - Part 1: Endothermic
Vinegar
General Observations
Exact Temperature
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Vinegar + Baking Soda
Part 1 - Analysis Questions:
1. How do you know a reaction occurred?
2. How did the temperature of the vinegar change when combined with baking soda?
3. Why do you think this happened?
Endothermic /
Exothermic Lab - Part 2
Hypothesis:
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If I combine water and calcium chloride then the temperature of the water will _____________.
Materials - Part 2 - Exothermic
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Plastic Bag
Graduated Cylinder
Measuring Spoons
Thermometer
Water
Calcium chloride
Procedure - Part 2 - Exothermic:
1. Pour 20 mL of water into an empty plastic bag. Feel the bag. Observe and record how the temperature feels in
the data table below.
2. Place the thermometer in the bag. Make sure the bulb of the thermometer is in the water.
3. Record the temperature below. Leave the thermometer in the bag.
4. Carefully pour 5 g of calcium chloride into the water and gently mix.
5. Wait 30 seconds and record the temperature again.
6. Remove the thermometer from the bag and carefully zip the bag.
7. Feel the bag again and note how the temperature change feels in the data table below.
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Data - Part 2: Exothermic
Water
Water + Calcium Chloride
General Observations
Exact Temperature
Part 2 Analysis Questions:
1. How do you know a reaction occurred?
2. How did the temperature of the water change when combined with calcium chloride?
3. Why do you think this happened?
Part 1 and 2 Analysis Questions:
Read the “What Was Happening” article and answer the following questions.
1. What does endothermic mean?
2. What does exothermic mean?
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3. Complete the table below for Part 1 of the lab.
Reactants
General Name
Products
Baking Soda + Vinegar
_____________ + _____________ + _____________
Compounds
NaHCO3 + CH3COOH
_____________ + _____________ + _____________
4. Complete the table below for Part 2 of the lab.
Reactants
General Name
Compounds
Products
____________________ + _________________
CaCl2 + H2O
Calcium Oxide + Hydrochloric Acid
CaO + 2HCl
5. What is a common use for calcium chloride?
6. Explain why calcium chloride would be helpful in the winter. Make sure you mention temperature changes and
how this might help.
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Endothermic and Exothermic Device Lab Instructions
Challenge:
● You must design a self-cooling device or object. You can design any type of device, but your design
must use the chemicals to cool it in a safe way. Your device can be for any situation where it might be
useful: everyday use, military, skiing, hiking, fishing, boating, etc.
Materials:
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Plastic Bag / Beaker
Graduated Cylinder
Measuring Spoons
Thermometer
Water
Acetic Acid
Sodium Bicarbonate
Calcium chloride
Procedure:
1. Brainstorm an idea for a device you think should be created. Write that device and its description
below. Feel free to draw pictures!
2. Why would your device be useful / necessary?
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3. Which combination of solids and liquids would be most useful in your device?
Sodium Bicarbonate and Acetic Acid
Calcium chloride and Water
4. Your next step is to decide how much of each solid and liquid you would need to use in your device. To
help you, complete the steps below.
5. Determine which 4 ratios you plan to use for your test. You can choose from the ones below or create
your own
● Maximum amount of samples combined:
● 20 g solid or 20 mL liquid
● Examples:
2 g solid to 2 mL liquid (1:1)
2 g solid to 4 mL liquid (1:2)
4 g solid to 2 mL liquid (2:1)
2 g solid to 6 mL liquid (1:3)
6 g solid to 2 mL liquid (3:1)
2 g solid to 8 mL liquid (1:4)
8 g solid to 2 mL liquid (4:1)
2 g solid to 10 mL liquid (1:5)
10 g solid to 2 mL liquid (5:1)
6. Write the ratios you plan to use in the data table below
7. Confirm your ratios with your teacher
● YOU MUST CONFIRM YOUR RATIOS BEFORE YOU START TESTING
8. Test the ratios on your data table and record your results
● Make sure you take careful measurements
9. Clean up your lab station
10. Answer the analysis questions
Data Table:
Solid Amount
Liquid Amount
Ratio
Temperature Before
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Temperature After
Change in Temperature
Reflection:
1. Which ratio would be the best for your device?
2. Why is this ratio the best?
3. Are there any other ratios you would like to test? If so, why?
4. How did the thermal energy change as you mixed the solid and the liquid together?
Thermal energy was released
Thermal energy was absorbed
5. What type of reaction occurred?
Endothermic
Exothermic
6. If you had to actually design your device, what areas might be an issue / what problems would still
need to be worked out before your device could be sold?
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