Density of Liquids Lab - Sierra Vista Chemistry



Density of an Unknown

Introduction:

In this investigation, you will first determine the density an unknown liquid by finding the mass and volume of the substance. You will compare your measured values with the accepted values for the densities of some common liquids to help identify the unknown liquid.

Materials:

Safety goggles

analytical balance

10 mL graduated cylinder

unknown liquid

Beryl Pipettes

Procedure:

Determining the Density of the Unknown Liquid

1) Mass a 10-mL graduated cylinder to the nearest 0.001 g and record data in Table 1.

2) Fill the graduated cylinder with 2.0 mL of the unknown liquid and mass it again. Record in Table 1.

3) Determine the volume of the liquid from step 2 by reading the value on the graduated cylinder. Read the bottom of the meniscus at eye level to the nearest 0.1 mL. Record data in Table 1.

4) Repeat steps #2-3 by increasing the volumes of the liquid by 2 ml for each trial until you reach 10 ml.

5) Empty the graduated cylinder.

Data

|Volume of Liquid (ml) |Mass of Cylinder + Liquid (g) |Mass of Cylinder (g) |Mass of Liquid (g) |

| | | | |

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| | | | |

| | | | |

In an Excel document graph your data and paste it into this document below.

Remember, to include both axis titles, plot the volume along the x-axis and the mass along the y-axis. Include units in your axis titles. Draw a best fit line.

Critical Thinking Questions:

1. Based on your graph, write a mathematical relationship between the volume and mass of the unknown liquid. (Hint: y = mx + b)

2. Find the slope of the line, what does this represent?

3. Assuming you have 150 ml of water, predict the mass of the liquid.

4. Using this number, use the chart below to identify the substance. Circle or highlight it before submitting.

[pic]

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