Name Determining the Density of Liquid and Solid Substances ab 1. Should you use
ID: 573430 • Letter: N
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Name Determining the Density of Liquid and Solid Substances ab 1. Should you use your bare fingers when handling a graduated cylinder, a rubber stopper and a piece of metal during this lab? If not, which tool should you use? 2. Name the method that is used in part IIl of this lab to determine the volume of a metal sample. 3. A test tube contains four liquid layers: chloroform, diethyl ether, mercury and water. Write a name of each layer on the sketch on the right. A marble with the density of 2.7 g/em) is dropped in the cylinder. Where will it rest (draw it)y? Substance Chloroform Diethyl ether Ethanol Mercury Toluene Water Density g/mL (at the room temperature) 1483 0.708 0.789 13.534 0.867 1.000 4. A student has measured the volume of an unknown liquid sample to be 5.50 ml. and its mass to be 4.32 g. What is the density of the liquid? Show your work Do not forget about the units and significant figures. Use the table above to identify the liquid. Density The liquid is 5. Someone sold you a ring and told you it was a gold one. Just to double check you decided to figure out its density. You weighed it and found the mass to be 21.25 g. The volume of the ring was measured by displacement. After it was placed in a graduated cylinder with 37.0 mL of water, the volume of water increased to 39.5 mL What is the density of the ring? Is it gold? The density 14K gold ranges form 12.6 to 14.2 g/cm2, that of 10K gold rages from 11.0 to 11.6 g/cm.Explanation / Answer
1. We should not use bare fingers, rubber stoppers or metal for the experiment as all of these may either react with the solution in consideration or would add impurities to the glassware when handling resulting into an error for the final measurement and the result. Instead one must handle the glassware using proper safety gloves (nitrile gloves), glass stoppers and glass rods when needed to avoid such a situation.
2. Displacement method is used to determine the volume of the system in this case.
3. The test tube would have the layers starting from the bottom (highest density first) - Mercury than Chloroform, followed by water and at the top (lowest density liquid) diethyl ether would be present.
When a marble of density 2.7 is dropped in the test tube, it would go and sit below the chloroform in the mercury layer or slightly above it as the density is greater than chloroform but lower than mercury.
4. Given volume = 5.50 ml
given mass = 4.32 g
so,
density = mass/volume
= 4.32 g/5.50 ml
= 0.78 g/ml
The liquid is = Ethanol [matching with data in the table]
5. Density of the ring = mass/volume
= 21.25 g/(39.5 - 37) ml
= 8.5 g/ml
Is it gold - Since the density found was below the given range for 14K and 10K gold, it may not be gold (or may be the ring is having very low gold content).
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