Density: A Graphical Relationship between Mass and Volume!

Honors Lab

A useful way of comparing two substances is to compare their densities. By carefully measuring the mass and volume of two substances, their densities can be calculated as follows: Density = mass/volume

It is generally given in units of g/ml. Density is a physical property which is often used to identify a substance. Materials that are less dense than water will float in it and those that are more dense than water will sink. In this experiment, you will determine the density of different substances form mass and volume measurement and calculate the 5 error in your results.

Materials

Balance- to the .1th place

10 and 100 ml graduated cylinder

sample of aluminum or pvc plastic

water, rubbing alcohol

Procedure 1 (Use your 10 ml graduated cylinder)

  1. Record the mass of an empty pipette using the balance.
  2. Fill a pipette with any amount of water. Dry the outside of the pipette and reweigh it on the balance.
  3. Calculate the mass of the water. (Mass of the pipette & water – Mass of pipette)
  4. Completely empty the water into a dry 10-ml graduated cylinder and record the volume to the 0.1th place.
  5. Repeat steps 1-4 for alcohol.

Data Table : Part 1

Water

Mass of empty pipette / g
Mass of pipette and water / g
Mass of water / g
Volume of water / ml

Alcohol

Mass of empty pipette / g
Mass of pipette and alcohol / g
Mass of alcohol / g
Volume of alcohol / ml

Procedure 2 (Use your 100 ml graduated cylinder)

  1. Do you have a plastic or aluminum sample? Find the mass of the sample sample at your station using your balance and record in the data table.
  2. Find the volume of the sample using Water Displacement:
  1. Add enough water to a graduated cylinder so that your sample would be

covered and record the volume to the 0.1th place.

  1. Carefully drop the sample into the graduated cylinder (NO SPLASHING) &

record the new volume of the water after the addition of the sample.

  1. Calculate the volume of the sample and record in the data table.

(Volume of cylinder after – Volume of cylinder before)

3. Remove thesample from the graduated cylinder and leave on your lab station.

Data Table: Part 2

Sample : Circle: PVC or Aluminum

Mass of sample / g
Initial Volume of water in grad cylinder / ml
Final Volume of water in grad cylinder / ml
Volume of sample (water displaced) / ml

Calculations: Show all work. Make sure answers have proper units and significant figures.

  1. Calculate the density of the water sample.
  2. Calculate the density of the alcohol sample.
  3. Calculate the density of the metal or plastic solid sample.
  4. Calculate the percent error for each of the 3 substances.

Accepted Density @ 25°C
Water / 1.00 g/ml
Alcohol / .79 g/ml
Aluminum / 2.70 g/ml
plastic / 1.40 g/ml
Copper / 8.92 g/ml

% error = |Accepted Value- Experimental Value| x 100

|Accepted Value|