chemistry

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Name: ID # Date:

Determine the Density of the Mystery Materials!

Can a material be identified by measuring its density?

Definitions Mass - the amount of matter in an object Weight - the force exerted on an object due to gravity Volume - the amount of space an object occupies Density - a number found by dividing an object's mass by its volume Meniscus - the curvature of the surface of a liquid caused by the liquid interacting with the walls

of its container Balance - a device that is used to measure an object's mass Scale - a device that is used to measure an object's weight

Practice Measurements How much liquid is in each graduated cylinder?

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Procedure 1. To do this experiment, your team will need:

• 2 samples of 3 unknown materials • A graduated cylinder • An electronic scale • A beaker of water • A small eye dropper

2. Obtain a sample of one unknown material and determine its mass with the scale.

3. Record the mass of the sample on the data chart.

4. Partly fill the graduated cylinder with water from the beaker. You can use the eye dropper to add small amounts of water to get the level to a 'nice' level. Make certain that there is enough water in the graduated cylinder to completely submerge the sample, but not so much water that the graduated cylinder will overflow when the sample is placed in it.

5. Record the volume of water in the graduated cylinder on the data chart.

6. Place the sample in the graduated cylinder. The water level in the graduated cylinder will rise because the sample has a volume, too. Since the water can't go into the space that the sample is occupying, the water gets 'pushed' out of the way, causing the level to rise.

7. Record the new level on the data chart.

8. Pour the water in the graduated cylinder back into the beaker and return the sample.

9. Repeat steps 2 through 8 with a second sample of the same unknown material.

10. Repeat steps 2 through 9 with two more unknown materials.

11. Calculate the densities of each of the unknown materials.

12. Use the calculated densities and the Densities of Common Materials chart to identify the three unknown materials.

Volume of Water = 20.0 mL Volume with Sample = 32.5 mL Volume of Sample =

(

(

(

Data Collection and Analysis

Sample 1

Sample 2

Mass of Sample

Material 1 Volume of Water

Volume with Sample

Volume of Sample

Density of Material 1

Total Mass ( + ) = =

Total Volume +

Sample 1

Sample 2

Mass of Sample

Material 2 Volume of Water

Volume with Sample

Volume of Sample

Density of Material 2

Total Mass ( + ) = =

Total Volume +

Sample 1

Sample 2

Mass of Sample

Material 3 Volume of Water

Volume with Sample

Volume of Sample

Density of Material 3

Total Mass ( + ) = =

Total Volume +

= =

)

= =

)

= =

)

Conclusions

Material 1 appears to be .

Material 2 appears to be .

Material 3 appears to be .

Questions to Think About 1. Is knowing an object's density always enough information to identify what it is?

2. Water has a density of 1.00 g/cm3. Two of the materials listed on the Densities of Common Materials chart will float on water. Which are they?

3. Boats are made from steel. Steel is mostly iron. If iron is denser than water, why do boats float?

4. Which is denser, 100 kilograms of aluminum or 1 kilogram of lead?

Sodium 0.97 g/cm3 Tungsten 19.3 g/cm3 Titanium 4.5 g/cm3 Uranium 18.95 g/cm3 Zinc 7.13 g/cm3

0.53 g/cm3 13.53 g/cm3 8.91 g/cm3

21.46 g/cm3 10.50 g/cm3

Lithium Mercury Nickel Platinum Silver

Aluminum 2.70 g/cm3 Copper 8.93 g/cm3 Gold 19.28 g/cm3 Iron 7.87 g/cm3 Lead 11.34 g/cm3

Densities of Common Materials

Complete the Table Below where the values are missing. Show your Calculations and box your answers. Attach your calculations to the end of this submittal.