Swamy Florida International University
Swamy Florida International University
CHM 1020L Density
This lab uses the following simulation https://www.pbslearningmedia.org/resource/arct15-sci-densitylab/density-lab/
If the link does not work for you it can also be accessed using the following link https://www.simbucket.com/simulation/density-lab/ Learning objectives
1) Understand the concept of density 2) Relate the value of density of a substance to the physical characteristics of the
substance. 3) Predict the effect of volume on density of pure substances 4) Predict the effect of mass on density of pure substances 5) Organize a given list of substances from least dense to most dense with supporting
evidence. 6) Apply knowledge gained in the experiment to explain relevant real-world situations. 7) Apply knowledge gained in the experiment to create a density gradient column.
Introduction Density is a characteristic physical property of a substance which means each substance has its own characteristic density that can use used to identify it. All substances have density including parts of the human body. Have you heard of the term osteoporosis? This happens when the density of human bones reduces, making them susceptible to fractures1. Lets get oriented first : ) Go to the following website https://www.pbslearningmedia.org/resource/arct15-sci-densitylab/density-lab/ You need not download the simulation but if you click on it, it will open on your computer. If you have technical issues please reach out to FIU Online technical help to get the issues resolved in a timely manner (details on how to reach FIU technical help are on the course homepage). Once you have the simulation open it should look like the figure shown below. Examine the figure shown below and ensure that you identify the parts on the simulation that are clearly marked. This will allow you follow directions and to perform the experiment stress free 1Chemistry a Molecular Approach, Nivaldo Tro, second edition (2011)
Swamy Florida International University
Please familiarize yourself with the following parts of the simulation (play with the simulation a bit to familiarize yourself with it)
1) Button to select water as the liquid 2) Check to see if the fluid density is 1.00 g/mL if you already selected water as your liquid. 3) Reset button 4) Balance to check mass 5) The display that shows you the mass of the material 6) Meniscus for volume 7) Location to choose materials to determine density 8) Location to change mass 9) Location to change volume
Procedure Part 1 – Let’s define some terms first Initial volume – volume of just the water (without the red block in the water) Final volume – volume with the red block in the water Change in volume = Final volume – initial volume (this should be a number greater than zero)
Swamy Florida International University
Section 1 – Relationship of mass and volume 1) Press the reset button (label #3) to clear the simulation 2) Press the “Turn fluid into water” button (label #1) 3) Check to ensure the fluid density is 1.00 g/mL since we are working with water (label #3) 4) Notice that the red block is floating above the water. 5) Move the blue mass button to around midway until the red block is completely
submerged in the water. 6) Note down the final volume of the meniscus in mL (volume with the red block in the
water) in Table 1 7) The balance should be at 0.0 grams – please check that.
8) Then take the red block and move it onto the balance taking care to place it in the center of the balance.
9) Leave the red block on the balance for now. 10) Record the mass of the red block in Table 1. 11) Is there a change in volume? Note down the initial volume of the meniscus in mL. (volume
of just the water ….without the red block in the water) 12) Enter the initial volume into Table 1
Swamy Florida International University
13. You have completed one observation. Second observation 14. You need to change the mass by moving the blue ball a little to the right and go thought steps 1-12. This will be observation 2. Third observation 15. Then you need to change the mass one more time by moving the blue ball a little more to the right and go through steps 1-12. This will be observation 3. Fourth Observation 16. Next move the blue ball all the way to the right so that the block sinks to the very bottom. go through steps 1-12. This will be observation 4.
Swamy Florida International University
Fifth Observation 17. Remember you need two more observations making sure that the red block is submerged in the water. So keep the blue ball to the very right and make changes with the volume by moving the red ball only, making sure that the red block is submerged in the water. Complete observation 5 by changing the volume and not the mass Sixth Observation 18. Remember you need two more observations making sure that the red block is submerged in the water. So keep the blue ball to the very right and make changes with the volume by moving the red ball only, making sure that the red block is submerged in the water. Complete observation 6 by changing volume again one more time but not the mass. Table 1 Effect of changing mass and volume on density (make sure you include units)
Observation number
Mass Final volume (Vf)
Initial volume (Vi)
Change in volume (DV) = Final volume (Vf) – initial volume (Vi)
Mass/DV (Do the calculation and plug in the number)
1
2
3
4
5
6
Swamy Florida International University
Part 2 – Density of same material when you change the liquid
1) Press the reset button (label #3) to clear the simulation 2) DO NOT Press the “Turn fluid into water” button (label #1) yet. It should instead say fluid
density is 2.5 g/mL 3) Move the blue mass button and the red volume button around until the red block is
completely submerged in the water. 4) Note down the final volume of the meniscus in mL (volume with the red block in the fluid)
in Table 2 5) The balance should be at 0.0 grams – please check that. 6) Then take the red block and move it onto the balance taking care to place it in the center
of the balance. 7) Leave the red block on the balance for now. 8) Record the mass of the red block in Table 2. 9) Is there a change in volume? Note down the initial volume of the meniscus in mL. (volume
of just the water ….without the red block in the water) 10) Enter the initial volume into Table 2 11) Next Press the “Turn fluid into water” button (label #1) 12) Check to ensure the fluid density is 1.00 g/mL since we are working with water (label #3) 13) Do not touch the red and blue buttons 14) Repeat steps 4-10 and enter the data into table 2
Table 2 Effect of changing fluid on density (make sure you include units)
Obs #
Fluid density Mass in Final volume (Vf) in
Initial volume (Vi) in
Change in volume (DV) in ___ = Final volume (Vf) – initial volume (Vi)
Mass/DV (Do the calculation and plug in the number) Units?
1 1 some other liquid (fluid density = 2.5 g/mL)
2 water (fluid density = 2.5 g/mL)
Swamy Florida International University
Section 3 – Density of various materials in water For each material you can choose (label #7) please follow the same directions. I am using ??? as an example to show how you need to work with the simulation to gather data.
1) Press the reset button (label #3) to clear the simulation 2) Press the “Turn fluid into water” button (label #1) 3) Check to ensure the fluid density is 1.00 g/mL since we are working with water (label #3) 4) Note down the initial volume in the meniscus in mL 5) Choose “???” from the panel (label #7) and a unknown (green colored) bar should appear
inside the beaker.
Swamy Florida International University
6) Is there a change in volume? Note down the final volume in the meniscus in mL. 7) The balance should be at 0.0 grams – please check that. 8) Then take the gold bar and move it onto the balance taking care to place it in the center
of the balance. 9) Write down the mass of the unknown (???) bar. 10) Enter all the values into Table 3
11) Repeat steps 1-10 to get similar data for the gold, lead, foram, ice, iron, wood, and rubber and enter them into table 3.
Swamy Florida International University
Table 3 Examining different materials (don’t forget the units)
Material being used
How does the material behave when immersed in water
Mass Final volume (Vf)
Initial volume (Vi)
Change in volume (DV) = Final volume (Vf) – initial volume (Vi)
1
unknown
2
3
4
5
6
7
