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...