PhysicsLAB: Boyle's Law

Equipment and Setup

The apparatus we will be using consists of a syringe, test-tube clamps, ring stand, C-clamp, and assorted masses.

As you can see in the image to the right, you will be capturing a small amount of air in the syringe by closing the attached hose clamp.

Before starting, I recommend that you tape the tops of the metal hanger together so that they can not be pulled out of their plastic slots during the lab. You should also lubricate the rubber edges of the plunger that make contact with the inside of the syringe. Do NOT lubricate the interior of the syringe!

As shown below, you should clamp the ring stand to the table and use two burette clamps to support the syringe so that it does not tilt as weights are added to the hanger.

Measure the inner diameter of the syringe before you carefully inert the lubricated plunger. Then slide the plunger to a position between 10-11 ml and close the hose clamp. Next slightly depress the plunger a couple of times to establish its equilibrium position. It should bounce back to the same position. This will test to make sure that your apparatus is sealed and not loosing air.

Before adding any masses, make sure that the syringe is stable and cannot move and that its metal hanger is hanging straight downward.

Now you will make a data table of the amount of mass suspended from the hanger and the volume of gas in the syringe. You will start by suspending 0.250 kg and increase the mass by 0.100 kg increments until the mass hanger can not hold any further masses, or until the seal breaks and the plunger slides down to zero. It is recommended that you NOT remove and replace masses, but gently add each 100-gram slotted mass gingerly to the hanger. Relaxing the load to adjust and replace masses has resulted in the plunger losing its seal.

Data

What is the temperature of the room in Celsius?

What is the inner diameter of the syringe in cm?

What is the interior area of the syringe in m²?

trial	mass suspended	volume
	(kg)	(ml)

When you have finished taking your data, tear down your apparatus and remove the plunger from the syringe for storage. You will now use EXCEL to analyze your lab data.

All columns of data should have headers that state the variable and its unit of measurement. All graphs should have the same titles as stated in the lab directions.

Refer to the following information for the next three questions.

Initially create the graph of Volume (ml) vs Weight (N). On your spreadsheet include columns of data called Suspended Mass (kg), Weight (N), and Volume (ml).

Is this graph of Volume vs Weight linear?

yesno

Do these variables have a positive or negative correlation?

positive correlation since volume increased as the suspended mass increased
negative correlation since volume decreased as the suspended mass increased

Now add a line of best fit that is a power rule. What is the equation of your curve?

Refer to the following information for the next three questions.

Now create the graph of Volume (ml) vs 1/Weight (N^-1) . On your spreadsheet add a column of data called 1/Weight (N^-1)

Fit a line of best fit that is linear. What is the slope of your line?

What are the units for your line's slope?

What is the correlation coefficient of your line?

Refer to the following information for the next two questions.

On your EXCEL spreadsheet add two more columns of data. The first one is called Absolute Pressure (in Pa) which equals atmospheric pressure plus (Weight/Area) from your data. The second column of data is Volume (m³).

Format both columns' numerical values to scientific notation with three decimal places.

Now graph Volume (m³) vs AbsPressure (Pa) . Make sure that the axes start at (0,0) so that you are able to complete Conclusion #2.

Do these variables have a positive or negative correlation?

positive correlation since volume increased as the pressure increased
negative correlation since volume decreased as the pressure increased

Now add a line of best fit that is a power rule. What is the equation of your curve?

Refer to the following information for the next three questions.

Now you will create your 4th and final graph in EXCEL. This graph will be Volume (m³) vs 1/Abs Pressure (Pa^-1) . You will need to add a new column of 1/absPressure. Make sure that you format the column's values to scientific notation with three decimal places.

What is the numerical value of this 4th graph's slope?

What are the units for the slope?

What is the correlation coefficient of your data's trend line?

Save your file as BoylesLaw_Lastname_Lastname.xlxs on the physics share. Format the spreadsheet so that all data tables and your four graphs are viewable on one printed page. Make sure that your group members names are present on the printed page. Print a copy for your lab notebooks as well as one for the instructor.

Conclusions

1. Use the slope of your final graph of Volume (m³) vs 1/absPressure (Pa^-1) to determine the number of moles contained in the syringe during the experiment.

2. Calculate the area of your third graph, Volume (m³) vs AbsPressure (Pa) , bounded between the graph and the y-axis.

3. What is the unit of measurement for this area?

4. What could this area represent based on its unit of measurement?

5. Which type of gas process did this experiment involve?

isobaricisothermalisovolumetric

6. Support your choice.