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I NEED HELP WITH COMPLETIGN MY LAB HOMEWORK. WE DIDNT DO THE LAB IN PERSON. THE PROFESSOR JUST SENT THE PAPER FOR ME TO COMPLETE. DO THE MEASUREMNT AND FILL IN THE SPACES THERE IS LAB #3
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Earth Science (PHSC 101) Virtual Lab Expt. #3: Density and Specific
Gravity
Name: ________________________ Section: _______ Date: ______
Note on this virtual Lab Experiment
Read the introductory principle, procedure and experimental materials outlined below, and understand as to how this virtual
experiment would be conducted under real lab condition to generate the theoretical data supplied in Tables below. After clearly
understanding the procedure and the formula for the calculations, enter calculated values in the blank columns and write brief
discussions as per the guideline, and resubmit the completed assignment in the Drop Box.
Introduction
Density
Density is a physical property of solids and fluids that can be defined as the mass (m) or quantity of a substance contained in
one unit of its volume (v).
The density of water is 1.0 g/ml (1g/cm3); in other words, 10ml has a mass of 10g.
Specific Gravity
Specific gravity of a body is that number which denotes the ratio of the mass of a body and the mass of equal volume water.
Specific gravity = Mass of solid or liquid
Mass of an equal volume of water
Water is used as the standard, because the density of water does not vary by more than 1/2 of a percent over the temperature
range of zero to 30-degree Celsius.
The density and specific gravity of any substance are numerically the same when the density is expressed in g/ml. When density
is expressed in g/ml (g/cm3), specific gravity can be calculated by dividing the density value by 1 g/ml (1g/cm3),thus making
it unit-less. Example, for copper: density is 8.5 g/ml (g/cm3); specific gravity is 8.5.
Standard specific gravities (densities) values of some materials are shown below:
Water
1.0 (1g/cm3)
Aluminum
Copper 8.5 (8.5g/cm3)
Steel
7.8 (7.8g/cm3)
2.7
(2.7g/cm3)
The main objective of this experiment is to determine the densities and specific gravities of different materials and compare them
with their standard values.
Materials and Procedure
Equipment
• Beakers
Graduated cylinders
• Analytical Balance Metal pieces (small)
• Metal rounds
Overflow-cup with nozzle
Experimental Procedure
1.
•
•
•
•
1.
Density of water
A 100ml graduate cylinder is filled with water more than half and read the exact volume in ml is read to one decimal
place, and record in Table 1, under the column designated volume of water (ml), Rep #1, third column.
A 150ml beaker is tared (zero) on analytical balance.
The volume of water in the cylinder is transferred quantitatively into the beaker; mass in grams of water in the beaker is
measured, and data record under mass of water (g), in the second column, Rep #1
The same procedure is repeated for Rep #2 and #3, the mass and volume data recorded in the appropriate columns.
Assignment
The theoretical data generated for mass and volume of water are already given in Table 1 below. From these data,
calculate the density and % error values, using the formulae given and enter values in the respective blank spaces (last
column):
• The density of water (d) is calculated by dividing the mass (m) in grams of water to the volume (v) of water in ml.
• The mean density values are calculated by adding the three replications and dividing by 3.
• The error % as compared to the standard density of water, which is 1g/ml, is calculated using the following
formula.
% Error = */Standard value – observed mean/ x 100
Standard value
*absolute difference (no negative sign)
Table 1. Density of water
Replicate
Mass of water
(g)
100
85
70
#1
#2
#3
Volume of water
(ml)
106
86
72
Density (mass/volume)
(g/ml)
Mean (average)
% Error
1.
•
•
•
•
•
•
2.
Density of pieces of metal (copper)
Some metal pieces (copper) provided are weighed on a balance (about 60g) and the exact weight in gram recorded
in Table 2, under mass (g) in column 2, Rep #1.
A 100-ml cylinder is filled to about 50 ml of water and exact volume in ml is recorded under the V1 column, Rep #1.
The weighed metal pieces are immersed into the water in the cylinder.
The new volume of water in ml is recorded under the V2 column in the data Table 2, which is the volume after
immersing the metal pieces.
The change in volume of water (V2 – V1) is calculated and recorded (This is the actual volume in ml of the metal
pieces).
This procedure is repeated in the same manner to complete Rep #2 and #3.
Assignment
The theoretical data generated following the procedure outlined above are given in Table 2 below. From these data,
calculate the density and % error values and enter in the last column blank spaces.
• Density of metal pieces is calculated by dividing mass of metal by change in volume, (g/ml)
• The mean density values are calculated by adding the three replications and dividing by 3.
• The error % as compared to the standard density of copper, which is 8.5g/ml, is calculated using the formula given
under density of water measurement.
Table 2. Density of pieces of metal
Volume (ml)
Replicate
Mass
(g)
Initial volume
of water
(V1)
Density Mass/volume
(g/ml)
Final volume of water
(V2)
Actual
volume
of metal
pieces
(V2 – V1)
15
25
44
#1
120
50
65
#2
200
50
75
#3
350
50
94
Mean (average)
% Error
1. 3.
Density of metal rounds (steel)
• The mass in gram of three metal round (steel) provided is measured one at a time and data entered in Table 3, under
column 2, Replications #1, #2, #3, respectively.
•
Overflow-cup with a drain-nozzle is placed on a bench above the water sink and filled with water until excess water
flows out through the nozzle and levels off.
After the excess water stops dripping out of the overflow-cup, an empty beaker is held under the nozzle with one hand
and the metal round, of which mass entered in Rep #1, is gently dropped in the water with the other hand; the metal
will displace a fraction of the water and water flows out through the nozzle into the beaker.
The content of the beaker is then poured into a small, graduated cylinder, and the volume is measured in ml and data
recorded under volume of metal column.
The experiment described for Rep #1 is repeated in the same manner for metal rounds 2, and 3, and data entered in
Row 2 and 3, in the appropriate columns.
•
•
•
Assignment
The theoretical data generated following the above outlined procedure are given Table 3 below. From the given data,
calculate and enter the density for each replication, the mean density value, and the % error of the experiment, using the given
formulae.
• The density (g/ml) of the metal is calculated for each replication by dividing the mass of metal round (g) by
the volume of metal (ml), and results entered in the last column.
•
The mean density values are calculated by adding the three replications and dividing by 3.
• The error % as compared to the standard density of steel, which is 7.8g/ml, is calculated using the formula given
under density of water measurement.
Table 3. Density of round metal (steel)
Replicate
#1
#2
#3
Mass of
metal
(g)
140
190
120
Mean
(average)
% Error
Volume of
metal (ml)
Density
mass/volume
(g/ml)
19
27
32
Discussion
In the space provided below, briefly discuss the results of each of your experiments by indicating the mean and percent
error values. Also indicate the level of precision of the experiment, by comparing the measurement results in the different
replications, as well as the level of accuracy of the experiment by comparing the means with their respective standard
values. Try to give explanation for the level of error obtained by indicating possible sources of error, if high % error (>10%)
is observed.
1. 1.
Density of water
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1. 2.
Density of metal pieces
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1.
3.
Density of metal rounds
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