1. Weigh the irregular solid provided by your instructor. Record its identity and mass on the report sheet.
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2. Fill the 100mL graduated cylinder between 50 mL and 70 mL with water.
3. Record this initial volume (V1) on the report sheet.
4. Gently place the irregular solid into the graduated cylinder. This is best accomplished by tilting the graduated cylinder and sliding the solid into the water. This will avoid splashing.
5. Record the new volume (V2) of water plus the irregular solid.
6. Determine the total volume displaced by difference (V2 – V1).
7. Calculate the density of the irregular solid by dividing the mass of the solid by the volume of water it displaced.
CHEM 1405 – Introductory Chemistry I
Determination of Density
CHEM 1405 – Introductory Chemistry I Determination of Density
Determination of Density
Report sheet
Name: Pratiksha Subedi Date:02/24/2021
Instructor: Professor Adhikari Section: 42004
Pre-lab Questions
1. What is the relation between density, volume, and mass?
Ans:
Mass, volume and density are three of an objects most basic properties. Mass is how heavy something is, volume tells you how big it is, and density is mass divided by volume. If you know the mass and volume of an object , you can figure outs its density by dividing the mass by the volume (D=M/V) and mass by multiplying the density times the volume (M=D*V).
2. How does one find the density of a regular-shaped solid? An irregular-shaped solid?
Ans:
I. Density of a Regular Solid
1. Identity of the item used as the Regular Solid: iPhone 12
Be sure to express the measured values consistent with the rules of significant figures.
|
Data Table 1 – Density of a Regular Solid
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mass of regular solid (step #2)
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164g
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length of regular solid (step #3)
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14.67 cm
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width of regular solid (step #3)
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0.74 cm
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height of regular solid (step #3)
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7.15 cm
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volume of regular solid (step #4)
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77.62 cm^3
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Remember to include units when recording measured values on the Data Table.
2. Density of the Regular Solid: 2.11 g/ cm3
II. Density of an Irregular Solid
1. Identity of the item used as the Irregular Solid (if an unknown sample, provide the unknown’s number):_____________________________________________________________
Data Table 2 – Density of an Irregular Solid
mass of irregular solid (step #1)
initial volume of water only, V1 (step #3)
volume of water + irregular solid, V2 (step #5)
2. Total volume displaced by the Irregular Solid: _____________________________________
Show calculations:
3. Density of the Irregular Solid: ____________________________________________________
Show calculations:
III. Finding the Density using Graphing Technique
Data Table 3 – Finding the Density using Graphing Technique
initial volume of water (step #1) (V0)
mass of first 5 pennies (step #2) (M1)
volume of water + first 5 pennies (step #3) (V1)
M2 (step #5)
V2 (step #6)
M3 (step #7)
V3 (step #7)
M4 (step #7)
V4 (step #7)
M5 (step #7)
V5 (step #7)
Remember to include units when recording measured values on the Data Table.
1. Determine the density of the pennies by calculating the slope of the line created by plotting the datapoints. (step #12)
Show calculations:
2. Density of the pennies using graphing technique (step #13): __________________ g/mL
3. Identity of the metal which comprises a penny (step #15): __________________________
Remember to attach the video recording of the student performing this section of the lab experiment to the report sheet either as a file attachment or as a link to a YouTube video. Failure to provide this video will result in a grade of ZERO on this lab assignment.
IV. Procedure to find Density (slope) using Excel
1. Density (calculated slope of the trendline) (step #14): _________________________ g/mL
2. Identity of the metal from which a penny is made: _________________________________
3. Attach a copy of the scatter chart created using Excel, including the line and line equation as generated with the program.
Questions: (show calculations!)
1. 575 g of an organic solvent is needed for an experiment. If the density of the organic solvent is 0.785 g/mL, what is its volume of organic liquid needed in mL?
2. What is the mass of a solution that has a density of 1.125 g/mL and a volume of 80.0 mL?
3. Why does a helium-filled balloon rise in air?
4. Which graphing technique seems to be the more accurate technique in finding a density: creating a hand-drawn graph on graph paper or using the Excel program to generate a Scatter Chart? Why?
REMEMBER:
·
Attach the photo of the completed hand-drawn graph from section “III. Finding the Density using Graphing Technique”.
· Attach the video of the student’s execution of the experimental procedures from section “III. Finding the Density using Graphing Technique”.
· Attach the photo of the scatter chart from section “IV. Procedure to Find Density (slope) using Excel.”
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Dr. Prem Adhikari 08/2020
Page 2 of 2
Dr. Prem Adhikari 08/2020
