Take Home Lab #6

Take Home Lab #6: Boyle’s Lab

Question: How do different items react to changes in pressure?

Answer all the questions label Q1 through Q10

Safety: Do not eat or drink any materials. Clean up spills immediately.

Materials: syringe, water, marshmallows, soda

WASH OUT THE SYRINGE AFTER THE CONCLUSION OF THE LAB!

Procedure: In this lab, you will investigate how different substances react when compressed or expanded in a syringe. You will put air, water, marshmallows, and soda in the syringe and make observations.

1. Air: Put your finger over the syringe with the plunger at the halfway point and press down on the plunger.

    Q1: How far were you able to squeeze the air?

With the tip still covered, pull the syringe out as far as you can.

    Q2: How far were you able to expand the air?

2. Water: Fill the syringe with water, trying not to allow any air bubbles. Put your finger over the end of the syringe and press down on the plunger.

    Q3: How far were you able to squeeze the water/

    Q4: Which is more compressible, gases or liquids?

3. Marshamallow: Put a small marshmallow in the syringe. Put your finger over the end.

    Q5: What happens to the marshmallow when you pull out the plunger?

    Q6: What happens to the marshmallow when you push down on the plunger?

    Q7: Explain your observations about the marshmallow.

4. Soda: Put some soda in the syringe and put your finger on the end.

 (be sure the soda isn’t flat before you begin).

     Q8: What happens to the soda bubbles when you push down on the plunger?

    Q9: What happens to the soda bubbles when you pull the plunger out?

    Q10: Explain your observations about the soda. Keep in mind your knowledge about volume and pressure in gases.

BE SURE TO WASH OUT YOUR SYRINGE AFTER YOU FINISH SO YOUR SYRINGE DOES NOT GET STICKY!

Ideal Gas Law & Soda Lab

Ideal Gas Law and Soda

Objective: To determine the amount of carbon dioxide in a can of soda by using the Ideal Gas Law.  By weighing the can, you can determine the mass lost and thus determine the moles.  The temperature and atmospheric pressure can be also determined to find the volume of the gas.  We can also compare results between regular and diet soda to determine if there is a difference in the amount of carbon dioxide they contain.

Directions:

1. Determine the atmospheric pressure in Los Angeles today. Convert to mm of Hg then you will need to convert to atmospheres.

2. Weigh your unopened can on the balance.

3. Every two minutes weigh the can again to see how much mass is lost.

4. Record the temperature of the soda in the can, as this is also the temperature of the gas.

4. While you are waiting the two minutes to weigh again, start your graph.

5. On the x-axis graph the time in minutes and on the y-axis graph the mass of the can. The starting mass of the can should be the highest point on the y-axis.

6. After 24 minutes, determine the final mass lost and complete your graph.

7. Use the Ideal Gas Law formula (PV= nRT) to determine the volume of the gas released by the soda.

8. Paste your graph (make sure it is labeled) inside your composition book.

Data:

Air pressure in LA (in mm Hg) : _____________    

Air pressure in LA (in atm): _____________

Initial mass of can: __________                                   Final mass of can: __________

Temperature of can: __________

           

Post-Lab Questions:

1. Show your work to determine the volume of gas released by the soda use the PV= nRT. Make sure to show all of the steps of your work.

2. What do you think would be the affect if you did this experiment at a lower atmospheric pressure? Would it have a difference on the amount of gas released? (Hint: Think about your gas laws and the relationships.)

3. Which soda has more gas in it? Why do you think that one soda has more gas than another? Think about what is the composition of these sodas.

Homework for 3/2 (#1)

1) Read chapter 15
2) HW #1 pg. 527 #1, 3-6
3) Complete take home labs—composition books collected next week

Homework for 2/26

1) pg. 478 #1-3, 481 #25, #27-28
2) Chapter 13 Test Friday—bring calculator and cheat sheet!
3) All late homework for Chpt 13 due Friday!

Homework for 2/24

1) pg. 481 #21, 23 a-c, 24 a-c
2) Chapter 13 Test Friday—bring calculator!
3) All late homework for Chpt 13 due Friday!

Study Guide for Chapter 13 Test

Chapter 13 test on Friday, February 27th:
--Bring a calculator! Bring your cheat sheet!

Answers to practice questions on pg. 485
1. D  2.  C   3.  B  5.  A  7. B  8. A  9. D  10. A 
--Know what a barometer is, what it measures and how it works
--Know how to convert from one unit of pressure from another, including torr, atm, mm Hg, and psi.
    --Make sure to have all the conversions on your cheat sheet
    --Remember the three steps: what do you know, what do you want to know, what do you want to get rid of
    --Remember that mm Hg and torr are equivalent
    --Remember when doing conversions to start with your money (atm) and then convert to other units
--Boyle's Law
   --Know the formula for Boyle's law and how to use it
   --Know that it is an inverse relationship, if pressure goes up the volume will go down and opposite as well
   --Understand how it affects objects in real life such as at the top of a mountain or under water
--Charles' Law
   --Know the formula and how to use it
   --Know that is it a direct relationship. If the temperature goes up, so does the volume.
   --Understand how it affects objects in real life such as when heat is added
--Avogadro's Law
   --Know the formula and how to use it
   --Know that it is a direct relationship. If the moles go up, so does the volume.
--Ideal Gas Law
   --Know the formula and what each letter stands for
   --Make sure you have the constant (R) on your cheat sheet
   --Make sure to remember that the units have to be atm, moles, Kelvin, and liters. If not YOU MUST convert to correct units
   --Know how to change the Ideal Gas Law if the conditions for the gases change in order to compare a gas before and after the conditions change

Homework for 2/23

1) Take home lab #5
2) pg. 459 ex 13.8, pg. 460 ex 13.9, pg. 461 ex 13.10, pg. 473 #2-3, pg. 481 #21, 23-25
3) Finish argument graphic organizer for candle activity

Homework for 2/19

1) pg. 480-1 #15-20
2) Make sure all coins are weighed will discuss on Thursday
3) Late composition books due Friday

Homework for 2/17

Sorry this did not get posted earlier, my computer shut down and I couldn't see my powerpoint to post the homework.

1) pg. 457 ex 13.7, pg. 457 #7 pg. 480 #15-17, 19-20
2) Make your measurements of the the four coins for take home lab #1

Take Home Lab #1: Weighing coins

Take Home Lab #1: Building Your Balance

Question: How does a single-beam balance work?

Safety: use only clean water in your syringe. Slowly push the plunger to avoid splashing the water. Never work near an electrical outlet or source. Clean up any spills when finished to avoid slips and falls.

Materials: 2 small cups (preferably plastic), plastic ruler, pencil, penny, nickel, dime, quarter

Procedure:

You will need a simple balance for many of the activities in this book. To build your balance, you will put a cup on each end of the ruler and balance the ruler on a pencil or pen placed under the middle of the ruler. Attach the cups with tape or glue, then make adjustments in the balance point by adding small extra pieces of tape or clay until the ruler is balanced. When balanced, the ruler may not be perfectly level, but you will be able to tell that tapping it can cause it to sway to either side. When the ruler is not balanced, it will only sway to one side. You should check the empty balance point before EACH time you use it and make adjustments as necessary. The object that you want to find the mass of should be put in one cup, then you can use the syringe to fill the other cup with water until you have a balance, recording in your lab notebook the beginning and ending volumes in the syringe. Make sure that your balance is on a flat table with both cups over the table.  If one side gets too heavy, you do not want the whole balance to fall on the floor.

                Remember that the density of water is 1.0 g/mL.  That means that 1 mL of water has a mass of 1 g. If it takes 27 mL of water to balance

out the sample, then the mass of the sample is 27 g.

                This is just one type of simple balance. Other balances might hang from a string or involve other methods. If this one does not work well for you, investigate other methods online and build another type of balance. As long as the balance has a beam that can be balanced with water, it will be fine for all of these activities.

Testing Your Balance: Test your balance by finding the masses of four different coins, and record those masses in your science notebook. The accepted masses will be given to you by your teacher to ensure that you use the balance correctly.

Data:

1. Mass of penny __________ g

    Date on penny ___________

2. Mass of nickel ___________g

3. Mass of dime ____________g

4. Mass of quarter __________g

Post-Lab Questions:

5. What was the percentage difference between your measurement and the accepted mass (as provided by your teacher)? Percent difference = ([difference between the two answers] ¸ [accepted answer]) x 100.

6. What do you think was the biggest contributor to that difference?

7. What do you think is the lightest mass that you could find using this balance?

Homework for 2/12

1) pg. 453 ex 13.5; pg. 457 #6; pg. 480 #11-14
 2)  Finish all labs (4 in class labs & 3 take home labs)—composition books due Friday!
3) Open house on Thursday—extra credit for parents attending
4) Volunteers for open house—extra credit

Cartesian Diver Lab

Cartesian Divers

Objective: To construct a Cartesian diver to visualize the relationship between volume and pressure of Boyle’s Law.

Procedure: Follow the steps to make sure that your diver is able to rise and sink with a small squeeze of your plastic bottle. 

     a. Place three washers on the end of your pipette.

     b. Wrap a rubber band around the end to secure the washers but DO NOT close the pipette.

     c. Add green colored water to your pipette until it just floats below the water in your plastic cup.

     d. Make a line with the marker where the water lies in your pipette.

     e. Fill your plastic water bottle near to the top with water.

     f. Add your diver to your water bottle. 

     g. Add more water to your bottle so it is completely filled and close the cap on top.

     h. Give a squeeze to your bottle and your diver should sink to the bottom and return when you let go.

Observations:

1. Write down your observations of the diver. Make note of the position of the water and air inside the pipette at the top and the bottom of the bottle.

Analysis:

2. Explain from your observation why the Cartesian diver is able to rise and fall in the bottle. Use your knowledge of pressure, volume and density to explain what is occurring.

3. Experiment with the diver with different variables such as different amounts of water, different temperatures of water,ki different amount of weights. Tell what you researched and the results of your experimentation and tell what worked and what did not work.