Identification of Liquid substances Through Their Physical Properties

Prepared by:Rodney Pujadarodneyperu@yahoo.comDepartment of ChemistryLos Angeles Trade Technical College400 Washington Blvd, Los Angeles CAMarch 29th, 2010

Report No 4Identification of Liquid

substances Through Their Physical PropertiesName: Rodney Pujada

Lab Partner: Armin VossooghiI. Introduction

In this experiment, we identify a compound by its physical properties. These properties are known as intensive properties (density, solubility, boiling point, and other) and extensive properties (entropy, enthalpy, mas, volume, and energy). The most physical properties are solubility, boiling and melting point, and the solubility of the substance in water, alcohol, and methanol. Most substance is likely to be soluble in another substance if the two substances have similar structural feature or have comparable electronic properties. As a result, we compare ionic and very polar covalent substance will disolve in water.

Also, we identify the substance by density that is expressed in grams per militer, and the boiling point that is the temperature at which it is converted from liquid to gas. As a result, these intensive properties give us the identification of the substance.

II. Material

Thermometer, two test tubes, test tube rack, 10 rnL graduated cylinder, analytical balance, utility clamps, iron ring, test tube with sidearm, rubber hose, and wire gauze.

III. Procedure

3.1. Solubility:

a. Add 2 mL of the unknown liquid in two test tubes.b. Add 2 mL of ethanol en un test tube and 2 mL water in the other test

tube.c. Shake them, and observe if the unknown is soluble, insoluble, or

partially soluble; and record the results.3.2. Density:

d. Measure the mass of 10 mL graduated cylinder.e. Add 6 mL into the graduated cylinder.f. Weight the mass of the graduated cylinder with the

unknown liquid.g. Record your results.

3. Boiling Point

Rodney PujadaChemistry 101/ Section 4075Instructor: Hans LeeDays of class: Tuesday and Thursday

Time of class: 6.00 – 9:10 pmDate Due : October 5th,2010

h. Use a test tube with a sidearm. Clamp the test tube to a ring stand using a utility clamp.

i. Add 2 mL the unknown liquid with small boiling-chip into the liquid.j. The test tube is either suspended in 400 mL beaker filled with water

(hot water bath) in the hot plate at 250 °C.k. Insert a thermometer into the rubber stopper, which is used to cap the

test tube. The thermometer is above the liquid and is not touching the liquid.

l. Turn on the hot plate and warm the test tube with the water bath. m. Record the temperature that will start rising as the liquid boils. After a

certain period oftime. ft will reach a maximum value and stay at this value.

IV. Data and Calculation

Unknown sample: No 19 Run #1

1. Mass empty graduated cylinder 41.2583 g

2. Mass graduated cylinder and liquid 45.9440 g

3. Mass of unknown liquid 4.6857 g

4. Volumen of unknown liquid 6 mL

5. Density of unknown liquid 0.7809 g/mL

6. Boiling Point of unknown liquid 65°C

IV.1 Compare the solubilityData:First Test tube with water: …………………………….Solubility with waterSecond Test Tube with ethanol: ………………………Solubility with ethanol

IV.2 Calculate the density of the unknown liquidData:Volumen of unknow liquid : 6 mLMass of the empty 10 mL graduated cylinder = mgrad cyl = 41.2583 gMass of the graduated cylinder and unknown liquid = mgrad cyl + known liquid = mgrad cyl + known liquid = 45.9440 gMass of the unknown liquid: = ( munknown liquid = mgrad cyl + known liquid - mgrad cyl) = 41.2583 - 45.9440 = 4.6857 gmunknown liquid = 4.6857 gDensity:

Density = mass / volumen

Density of unknown liquid = 4.6857 g / 6 mL

Density of unknow liquid= 0.7809 g/mL

IV.3 Calculate the boiling point of the unknown liquidData:

Temperature of boiling pointV. Conclusions:

We test the solubility of unknown liquid in two different solvents. We find the density (0.78g/mL) of the liquid using a small 10 mL graduated cylinder with a margen of error; however, the solubility test and boiling point test (°65) help us to identify the substance in the figure No1.

This experiment shows any the physical properties of methanol. The methanol is soluble in water and etanol; its density is 0.79 grams per militer, and its boilig point is 65° C.

Intensive properties are extremely important, and they do not depend on the amount of matter present in a substance, also they help us to identify substances.

Temp = 65°C

Appendix:

Report No 4: Identification of Liquid Substances Through Their Physical Properties

Substances can be identified through their physical properties, such as solubility, melting point, boiling point, density, electrical and magnetic properties, physical state, and a variety of other physical properties.

In this experiment you will use only three physical properties, namely the density, the boiling point (because it is a liquid), and its solubility in two different solvents, to identify a compound.

Pure substances always have a sharp and fixed melting point for solids and a fixed boiling point for liquids. These temperatures are carefully measured and documented, thus making the measurement of melting or boiling point a powerful tool for identification purposes.

EQUIPMENT

Thermometer, test tubes, test tube rack, 10 rnL (or 25 mL) graduated cylinder, balance, utility clamps, iron ring, test tube with sidearm, rubber hose, and wire gauze.

Make a sketch of the boiling point aparatiis (this must appear on the left hand side of the notebook).

PROCEDURE

I. Solubility

Test the solubility of your unknown in two different solvents.

• 1 Place two of your dry and clean test tubes in a test tube rack, then mark them in terms of the solvent used.

1.2 Add a small volume (about 1 or 2 mL) of each solvent in the corresponding test tube, then add an equal volume of the unknown liquid to each test tube.

1.3 Shake your test tubes for a few seconds (do not use your finger to cover the test tube — ask your instructor for directions), then observe if the unknown is soluble, insoluble, or partially soluble.

1.4 Record your observation.

2. Density

Find the density of the liquid using a small graduated cylinder (10 mL or 25 mL).

2.1 Measure the mass of a dry and clean graduated cylinder.

2.2 Pour your unknown liquid into the graduated cylinder to at least half high.

2.3 Read the volume of the liquid.

2.4 Measure the mass of the graduated cylinder with liquid.

2.5 Record your results.

3. Boiling Point

3.1 Use a test tube with a sidearm. Clamp the test tube to a ring stand using a utility clamp.

3.2 Add a small volume of the unknown liquid (2 or 3 mL), then drop a small boiling-chip into the liquid.

3.3 The test tube is either suspended in a beaker filled with water (hot water bath) or placed on the wire gauze directly above the flame of the burner (you will be instructed what to do).

3.4 Insert a thermometer into the rubber stopper, which is used to cap the test tube. Make sure the thermometer is above the liquid and is not touching the liquid.

3.5 Attach a rubber hose to the sidearm and direct it away from the proximity of the flame.

3.6 I leat the test tube with a very low flame. You will notice that the temperature will start rising as the liquid boils. After a certain period oftime. ft will reach a maximum value and stay at this value.

3.7 Record this temperature, which is the boiling point of the liquid

RESULTS

(These results must be recorded on the right hand side of the notebook)

1. Solubility in Water Ethanol

(circle the answer) s i sl.s s i sl.s

* s soluble; i insoluble; sl.s = slightly soluble.

2. Density

Mass of cylinder plus liquid _______________________________________

Mass of empty cylinder _______________________________________

Mass of the liquid _______________________________

Volume of the liquid ________________ ________

Density of the liquid ______________________ ________

3. Boiling Point ___________ ______________

IDENTIFY THE UNKNOWN SUBSTANCE

Your unknown is one of the substances given in the following table of physical properties. Compare the set of properties that you measured to the substances listed in the table and identify your unknown.

CALCULATIONS

Perform your calculations on the right hand side of your notebook.

CONCLUSIONS

Give your unknown number and name your unknown. Use the left hand side of your notebook.

http://www.buzzle.com/articles/physical-properties-of-matter.htmlPhysical Properties of Matter

Physical properties of matter are categorized as Intensive Properties and Extensive Properties.

Intensive PropertiesIntensive properties are extremely important and they do not depend on the amount of matter present in a substance. In short, it is a property independent of the amount of mass. This is because every kind of matter possesses a distinctive set of intensive properties that distinguishes it from the other kind of matter. These include:

Color Odor: Signifies Smell

Boiling Point: The temperature at which the liquid boils at sea-level (generally atmospheric pressure)

Freezing/Melting Point: The temperature below which a liquid turns into a solid at atmospheric pressure

Density: The mass of a substance divided by its volume (D=M/V)

Luster: A shine on a substance

Malleability: The property of a substance to be beaten into thin sheets

Ductility: The malleability of a substance drawn into threads, wires into thin sheets

Conductivity: The ability of transmitting the flow of energy, electricity and sound

Hardness: The property of a substance being rigid and resistant to pressure

These are some of the common examples of intensive properties.

Extensive PropertiesSpeaking of extensive properties, these depend on the amount of matter present in a substance. That is, they vary directly with the mass, volume, etc. These include:

Mass: An amount of matter in a specific object Weight: A vertical force exerted by a mass on an object as a result of gravity

Volume: A substance occupying an amount of space in a given area

Length: An extension of a substance from beginning to the end