chemistry lab report, density

DENISTY LAB

2/25/13
Chemistry H.
Mrs. Halme

Objective: Your task is to determine the density of 3 known metals: Zinc, Copper, and Lead. They are each marked. You must then calculate the density of an unknown metal and determine its identity based on your data from your known samples.
Reagents: None

Equipment:
Lead
Copper
Zinc
Triple Beam Balance
Graduated cylinder
Unknown metal (Magnesium)
Beaker
Calculator

Procedures Preparation:
We observed the given equipment, and then placed 100 Ml of water into a graduated cylinder.
Zinc
1. We then placed a sample of Zinc in the graduated cylinder.
2. The water level rose 4 ml. We subtracted the original 100mLof water from the 104mL of water with zinc in it. This gave us the volume of the zinc, being 4mL.
3. We then took the sample of Zinc and placed it on the Triple beam Balance.
4. We recorded the mass of the sample at 36.5 g.
5. We then recorded our results.
6. Then we divided the mass of the Zinc by the volume. This giving us the density of the sample being 9.125 mL/g.
7. We found the %error to be 27.8%, by subtracting our result minus the accepted value of the sample, multiplied by 100% divided by the accepted value.

Copper
1. We then placed a sample of Copper in the graduated cylinder.
2. The water level rose 3mL. We subtracted the original 100mL of water from the 103mL of water with Copper in it. This gave us the volume of the Copper, being 3mL.

3. We then took the sample of Copper and placed it on the Triple beam Balance.
4. We recorded the mass of the sample at 13.8 g.
5. We then recorded our results.
6. Then we divided the mass of the Copper by the volume. This giving us the density of the sample being 4.6 mL/g.
7. We found the %error to be 48.4%, by subtracting our result minus the accepted value of the sample, multiplied by 100% divided by the accepted value.

Lead
1. We then placed a sample of Lead in the graduated cylinder.
2. The water level rose 6mL. We subtracted the original 100mL of water from the 106mL of water with Lead in it. This gave us the volume of the Lead, being 6mL.
3. We then took the sample of Lead and placed it on the Triple beam Balance.
4. We recorded the mass of the sample at 84.7g.
5. We then recorded our results.
6. Then we divided the mass of the Lead by the volume. This giving us the density of the sample being 14.12 mL/g.
7. We found the %error to be 24.5%, by subtracting our result minus the accepted value of the sample, multiplied by 100% divided by the accepted value.

Unknown (Magnesium)
1. We then placed a sample of the unknown metal in the graduated cylinder.
2. The water level rose 8mL. We subtracted the original 100mL of water from the 108mL of water with the unknown substance in it. This gave us the volume of the unknown metal, being 6mL.
3. We then took the sample of the unknown metal and placed it on the Triple beam Balance.
4. We recorded the mass of the sample at 14.83g.
5. We then recorded our results.
6. Then we divided the mass of the unknown metal by the volume. This giving us the density of the sample being 1.9mL/g.
7. We found the %error to be 9.2%, by subtracting our result minus the accepted value of the sample, multiplied by 100% divided by the accepted value.

Results
Calculation questions

Zinc calculations
Volume- We found the volume by placing the Zinc in a graduated cylinder filled with 100mL of water. We observed that the water level rose to 104mL. We then subtracted the original 100mL from the 104mL that contained the Zinc. This gave us the volume, being 4mL.
Mass- We found the mass of the Zinc by placing it on the triple beam balance. This gave us the mass, being 36.5g.
Density- We found the density by dividing the mass by the volume. 36.5g divided by 4mL. This giving us the density, being 9.125mL/g.
%Error- We found the % error by subtracting the density (9.125mL/g) from the accepted value (7.14g), Multiplied by 100%, then divided by the accepted value. This giving us the %Error, being 27.8%.

Copper calculations

Volume- We found the volume by placing the Copper in a graduated cylinder filled with 100mL of water. We observed that the water level rose to 103mL. We then subtracted the original 100mL from the 103mL that contained the Copper. This gave us the volume, being 3mL.
Mass- We found the mass of the Copper by placing it on the triple beam balance. This gave us the mass, being 13.8g.
Density- We found the density by dividing the mass by the volume. 13.8g divided by 3mL. This giving us the density, being 4.6mL/g.
%Error- We found the % error by subtracting the density (4.6mL/g) from the accepted value (8.92g/cm), Multiplied by 100%, then divided by the accepted value. This giving us the %Error, being 48.4%.

Lead calculations

Volume- We found the volume by placing the Lead in a graduated cylinder filled with 100mL of water. We observed that the water level rose to 106mL. We then subtracted the original 100mL from the 106mL that contained the Lead. This gave us the volume, being 6mL.
Mass- We found the mass of the Lead by placing it on the triple beam balance. This gave us the mass, being 84.7g.
Density- We found the density by dividing the mass by the volume. 84.7g divided by 6mL. This giving us the density, being 14.1mL/g.
%Error- We found the % error by subtracting the density (14.1mL/g) from the accepted value (11.3437g/cm), Multiplied by 100%, then divided by the accepted value. This giving us the %Error, being 24.5%.

Unknown calculations

Volume- We found the volume by placing the unknown metal in a graduated cylinder filled with 100mL of water. We observed that the water level rose to 108mL. We then subtracted the original 100mL from the 108mL that contained the Lead. This gave us the volume, being 8mL.
Mass- We found the mass of the unknown metal by placing it on the triple beam balance. This gave us the mass, being 14.82g.
Density- We found the density by dividing the mass by the volume. 14.83g divided by 8mL. This giving us the density, being 1.9mL/g.
%Error- We found the % error by subtracting the density (1.9mL/g) from the accepted value (1.74g/cm), Multiplied by 100%, then divided by the accepted value. This giving us the %Error, being 9.2%.

Data table and Observations

Sample
Mass
Volume
Density
%Error
Accepted value
Zinc
36.5g
4mL
9.125mL/g
27.8%
7.14g/cm3
Copper
13.8g
3mL
4.6mL/g
48.4%
8.92g/cm3
Lead
84.7g
6mL
14.12mL/g
24.5%
11.3437g/cm3
Unknown (magnesium)
14.83g
8mL
1.9mL/g
9.2%
1.74g/cm3

Written response questions
1. What is your unknown? How do you know?
The unknown is magnesium. We know this density we recorded is very accurate to what we got.
2. Is density a physical or chemical property? Explain.
Density is a physical property because the substance can change when the substance changes state.
3. Is density an extensive or intensive property? Explain.
Density is intensive because it doesn’t depend on a mass.

Conclusion

In this experiment we found mass, volume, density, and %Error. To find volume we used a graduated cylinder with 100mL of water and placed the different metals in it to see how much the water level rose. To find the mass we used a triple beam balance. To find the density, we divided the mass by the volume. To find the %error we subtracted the density we found from the actual density then multiplied that by 100%, then dividing that buy the accepted value. The error in our experiment most likely came from miscalculation. There were many parts in this experiment that we could have slightly miscalculated. In this experiment we learned to calculate density and %error, using volume and mass. We learned that we will have error in our experiments. We also identified an unknown metal as magnesium, by using measurements we found and some that were given.

Table of contents

1. Objective, Reagents and Procedures.
2. Procedures.
3. Procedures and Results (calculation questions).
4. Results (calculation questions).
5. Results (calculation questions).
6. Results (data table and observations), written response questions, and conclusion.
7. Conclusion.