Measurement of Heat Transfer Lab

Measurement of Heat Transfer

    The first law of thermodynamics says that heat added into a system changes into an equal amount of some other energy.  It is based on the law that says energy cannot be created or destroyed.  It can only change forms.  You can understand the law of thermodynamics if you understand a car engine.   Gasoline is burned.  The energy in its bonds is released.  That energy causes the gases in the combustion chamber to explode.  The explosion forces a piston to move.  The piston does work.  The heat energy put into the engine equals the increase of temperature inside the engine plus the work that the piston did.

Draw and explain the heat transfer in a car engine.  

    This next activity is a simpler way to show the law of conservation of energy.  You will measure the amount of heat lost by hot water and the amount of heat gained by cool water.  You will mix different amounts of hot and cold water together to determine their final temperature.You will mix different amounts of hot and cold water together to determine their final determine.

Procedure:

1. first write an objective and a hypothesis.

2. Put 60 mL of hot water in your cop. measure the temperature and record in your data table. Measure 60 mL of cold water and record temperature, then add to hot water. Stir the water gently until the temperature remains steady and then record in your table.

--Repeat the experiment with 30 mL of hot water and 60 mL of cold water.

Volume		Starting Temperature		Final Temperature	Temperature Rise	Temperature Drop
cool water	hot water	cool water	hot water	mixture	cool water	hot water

Answer the following questions in your conclusion:

3.  When you mixed equal volumes of hot and cold water, what happened to the temperature?  How did the temperature rise of the cool water and temperature drop of the hot water compare?

4.  Was the result what you expected?  What does this tell you about energy transfer in this activity?

5.  When you mixed only 30 mL of hot water with 60 mL of cool water, how did the temperature rise of the cool water and the temperature drop of the hot water compare?  How would you explain your results?

6.  Explain the First Law of Thermodynamics.  How does your experiment support the Law of Thermodynamics.  Describe data that support the Law.

Take Home Lab #4

Take Home Lab #4

Question: What state of matter is a colloid?

Safety: Do not try to save the cornstarch and reuse it. Mold grows quickly on cornstarch once it is wet, so dispose of it immediately. Wipe up any spills immediately. Do not consume the cornstarch after use. Dispose of the material in the trash.

Materials: shallow bowl, water, cornstarch

Procedure: The kinetic molecular theory helps one understand the difference between solid, liquid, gas, and plasma. A solid has a definite shape and volume. A liquid has a definite volume and takes the shape of its container. A gas fills its container completely and its volume changes with temperature and pressure.  A plasma fills its container and has a variable volume.

            In this lab, you will investigate a material called a colloid to determine its state of matter. You will see that determining the state of matter is not always as easy as it sounds. Colloids are not a separate state of matter, but they sure can act strangely.

1. Make the cornstarch colloid by adding 4 spoonfuls of cornstarch to 2 spoonfuls of water. It should be very thick but not dry. Make small adjustments by adding a little more starch or a little more water. It will dry out a little over time; just add more water to get the colloid back to its original condition. The colloid should get to the point where you can pick up a chunk of it and it turns into a liquid in your hand.

2. After each of the following tests, determine whether the colloids acted like a liquid or a solid:

            a. Tap the surface of the colloid quickly with your finger. Is it a solid or a liquid? __________

            b. Press your finger slowly into the colloid. (it will not hurt you; it actually makes your skin soft and will rinse off with water.) Is it a solid or a liquid?__________

            c. Try to stir the colloid quickly with your finger. Is it a solid or a liquid? __________

            d. Try to stir the colloid slowly with your finger. Is it a solid or a liquid? __________

            e. Tip the bowl from side to side. Is it a solid or a liquid? _________

            f. Grab a chunk and pick it up. Is it a solid or a liquid? __________

            g. Pour it from the bowl to your hand. Is it a solid or a liquid? _______

            h. Set objects of different densities on its surface. Is it a solid or a liquid? _________

Post-Lab Questions:

1. Is this colloid a solid or a liquid? Explain.

2. Many fine powders, such as the silt on the side of a river, can form colloids. Would it be dangerous to build homes or businesses on these riverbeds? Explain. Try a little experiment with your colloid to see what might happen.

3. Do you think you could make a colloid from salt, sugar, or baking soda? Based on your answer, which is one condition that must be met for a powder to form a colloid?

 

Homework for 2/2

1) All late HW due Monday!
2) Read Chapter 13
3) Take Home Lab #4

Homework for 1/29

1) pg. 354-6 #36-40, 43, 53, 56, 60
2) All late HW due Monday!
3) Composition books due Friday—make sure all labs are completed
4) Chpt 10 Quiz Friday—study guide online

Study guide for test for 1/30

Topics to study

--understand what energy allows us to do
--know the difference between potential and kinetic energy
--be able to explain what the law of conservation of energy states
--understand how energy is lost through heat in a system
--understand the difference between heat, temperature and thermal energy
--know what exothermic means and what will happen when a reaction is exothermic
--know what endothermic means and what will happen a reaction is endothermic
--know how to convert between calories and joules
--know how to use the formula Q =  s x m x DELTA (triangle) T
--be sure to know what each part of the formula represents
--understand the importance of energy in our world and the different sources

Pg. 357--Standardized test practice
1. B   2. C  3. B   4. D   5. A  6.  C   8. C  9. B  10. petroleum/natural gas  11. wood

Ice Investigation Lab

Ice/Water/Steam Investigation Lab

 
Objective:  To observe the temperature and heat of H₂0 as it changes state.  You will create your own procedure. You have at your disposal materials that you may choose to use. During the investigation, you will write the steps in your procedure and collect data.  At the end of the investigation, you are to provide a graph of your results and explain what you observed through the data of your graph.

Materials you can use: Hot plate, thermometer, balance, cups, beaker, stirrer, graduated cylinder, stopwatch on your phone.

In your composition book:

1. Provide a detailed list of your steps in your procedure.

2. Collect data and make sure it is legible and it is clear what you are collecting and units are used.

3. Create a graph of your data that you collected. (paste in composition book)

4. Write an explanation of what your data showed during your investigation as it relates to the ice, temperature and heat.  (Hint: Think about including words such as melting, boiling, heat, temperature, constant.)

5. According to your data and graph, what is the freezing temperature of water? The boiling temperature?

6. Look at the graph. During boiling does the temperature change? How long does it boil?

Energy Changes Lab

Part 1:  Reaction between HCl and NaOH Data Table

Temperature of mixture (C⁰): 

Temperature of HCl before mixing:           

Difference between two temperatures:    

Increase or decrease in temperature ?:

Exothermic or endothermic ?:

Part 2:  Reaction between NH₄NO₃ and H₂O Data Table

Temperature of mixture (C⁰): 

Temperature of H₂O before mixing:          

Difference between two temperatures:                            

Increase or decrease in temperature ?:

Exothermic or endothermic ?:

Part 3:  Reaction between NaOH and H₂O Data Table

Temperature of mixture (C⁰): 

Temperature of H₂O before mixing:          

Difference between two temperatures:                            

Increase or decrease in temperature ?:

Exothermic or endothermic ?:

Questions:

1. What happens in an exothermic reaction?

2. What happens in an endothermic reaction?

3. Which of the reactions were exothermic?

4. How do you know it was exothermic?

5. Which of the reactions was endothermic?

6. How do you know it was endothermic?

7. Draw a picture showing the flow of energy in Part 2 of the laboratory.