DENSITY LAB



Name _______________________

DENSITY LAB

Objective:

Using the quantitative property density, properly sequence various substances. In a graduated cylinder the student will create a distinct pattern of layers and suspend a solid.

Materials:

25-50 mL graduated cylinder 5 beakers (any size) stirring rod water

sugar food coloring potato slice pipette

Procedure:

1. Calculate: Calculate the amount of sugar needed to make the following solutions using dimensional analysis. Show your work on back page in calculations section. Write the calculated mass in Data Table #1 (use proper sig figs and unit labels).

Solution A = 20.0 mL of solution at .20g/mL concentration

Solution B = 20.0 mL of solution at .50g/mL concentration

2. Make Solutions A and B:

a. Place the correct amount of sugar for solution A into a beaker labeled “A”.

b. Measure 15 mL of water in a graduated cylinder and then add to the beaker of sugar (use warm water if available). Stir until dissolved

c. Pour this solution back into a 25 or 50 mL graduated cylinder to add the last drops of water with a pipette to create a final volume of exactly 20.0 mL. Pour into a beaker labeled Solution A

d. Repeat for solution B.

3. Calculate Density:

Calculate the density of solution A and solution B (D=M/V)

Mass: Please be very careful when doing this to prevent spilling on the balance!!

a. Mass an empty beaker and remove it from the balance.

b. Mass the same beaker after pouring in your solution A.

c. Write the mass of the solution in Data Table #2

d. Return solution A to its labeled beaker

e. Calculate the density. Show your work in calculations section.

f. Repeat steps (a-e) for solution B

Calculate the density of solution C (D=M/V)

Mass: Please be very careful when doing this to prevent spilling on the balance!!

a. Obtain exactly 20.0 mL of C in a 25 or 50 mL graduated cylinder

b. Determine the mass as described for solution A above

c. Record the mass and the calculated density for each in Data Table #2. Show your work in calculations section.

Calculate the density of solution D (D=M/V), just like you did with solutions A, B and C.

Calculate the density of a potato

a. Obtain a slice of potato from the designated location and determine its density. (Remember to determine volume by water displacement.) Record the appropriate data in Data Table #2 and show work in Calculations section.

4. Hypothesis: After all the densities are calculated, write a procedure below indicating in what order the solutions and the solid should be put into a density column to create distinct layers. Show your method to the teacher for approval before moving on.

METHOD:_____________________________________________________________________________

__________________________________________________________________________________________

INITIALS _________________

5. Experiment: Once approved, add a small drop of food coloring to each liquid. The lowest density liquid must be colored yellow. The next must be red, then green. The highest density must be blue.

6. Fill a gas tube (see me for tube) in the correct order using only 10.0 mL of each solution and the potato. Use a pipette to fill the graduated cylinder very slowly and carefully to prevent mixing. (Note: One lab partner should hold the gas tube while the other fills)

7. Have me check your column. It must have 5 different layers to get approval! INITIALS _____________

DATA TABLE #1

|Solution |Volume |Concentration |Mass of Sugar Used |

|A |20.0 mL |0.20 g/mL | |

|B |20.0 mL |0.50 g/mL | |

DATA TABLE #2

|Substance |Volume |Mass |Density |Rank Density |Assigned Color |

| | | | |1=highest | |

| | | | |5=lowest | |

|A |20.0 mL | | | | |

|B |20.0 mL | | | | |

|C |20.0 mL | | | | |

|D |20.0 mL | | | | |

|Potato | | | | | |

11. Draw a colored picture of the results.

CALCULATIONS: (Show all work here. Number your work. Pay attention to units and significant figures!)

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