Melting Points Lab Report Sample

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The aims of this lab are. as follows ; to understand what occurs at the molecular degree when a substance thaw ; to understand the primary intent of runing point informations ; to show the technique for obtaining the runing point of an organic substance ; and to explicate the consequence of drosss on the runing point of a substance. Through the experimentation of three substances. tetracosane. 1-tetradecanol and a mixture of the two. observations can be made in mention to runing point refering mutual opposition. molecular weight and pureness of the substance. When comparing the two substances. it is apparent that heavy molecule weight of tetracosane allowed it to defy the increased heat as a solid for a longer continuance. The runing point of the combined molecules was much lower than each in its pure signifier. The determination reinforces the thought of derived functions and their importance when placing a substance based on runing point. The decisions drawn from the information found in this lab will help in the acknowledgment of molecules based on the belongingss they illustrate.

IntroductionThe aims of this lab are. as follows ; to understand what occurs at the molecular degree when a substance thaw ; to understand the primary intent of runing point informations ; to show the technique for obtaining the runing point of an organic substance ; and to explicate the consequence of drosss on the runing point of a substance. In this unit of survey. I have learned that the physical belongingss of a molecule are normally relied upon for designation. More specifically. a chemical’s runing point is frequently the physical belongings of pick for designation. The runing point of a substance is defined as the temperature at which the solid and liquid stages of a substance are in equilibrium with one another and both present at the same clip. A molecule’s thaw point is straight related to intermolecular forces within the substance ; it describes its atoms attractive forces and how near the atoms are to one another within the compound. Using this cognition obtained from the class work. I will experiment with two given organic compounds to heighten my apprehension of runing points.

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METHODS AND MATERIALSSafety gogglesSpoonPaper towelsRubber sets ( 3 )Clean sheet of paper100ML beakerBurner fuelBurner fuel baseDuel magnifierThermometer- in- composition board tubingCapillary tubingsTetracosane Crystals- 0. 2gTetradecanol Crystals- 0. 2g

Experimental PROCEDURETo get down this experiment. I must pour about 60mL of H2O into a glass beaker. leting it to sit until room temperature is achieved. Following. I will pour the tetracosane crystals onto a clean sheet of paper crush them into a all right pulverization with the dorsum of a spoon. A little sum of the pulverization will be collected and placed in the underside of a glass capillary tubing. My end is to hold the power occupy no more than 2mm of tube infinite ; excessively much stuff will mislead a true thaw point. Once inside the tubing. I will procure the tubing alongside a thermometer with a little gum elastic set ; careful to put the underside of the tubing straight above the bulb of the thermometer. The finished construction is so placed into the H2O bath. It is critical at this point that H2O does non come in the glass tubing.

Once the compound is unafraid in the beaker of H2O. the full unit is placed onto the burner base. Ignite the burner fuel and bit by bit increase the temperate while closely detecting the compound for alterations. Use cautiousness in increasing the temperature bit by bit. as non to lose the right boiling point and change the information. A good criterion to follow is increasing the bath temperature by no more than 5 grades per minute. Note: a exaggerated glass is recommended to pay careful attending to the compound. Record the temperate when the first beads of liquid are noted. as the crystals begin to prostration ; besides. enter the temperature when all the crystals have become liquid. These two measurings are the runing point scope for tetracosane.

Once the scope is obtained. take the thermometer and beaker. Pour out the hot H2O and let both the thermometer and the beaker to chill. Once cool. reiterate the old stairss with the 2nd compound. tetradecanol. At the decision of the 2nd experiment. reiterate the stairss for a 3rd and concluding clip utilizing an equal mixture of both compounds. Be certain to enter the thaw point scope for all three experiments.

RESULTS AND DISCUSSIONMelting point scope for tetracosane: 49-51 grades CelsiusMelting point scope for 1-tetradecanol: 37-40 grades Celsius Melting point scope for mixture: 34-37 grades Celsius

I was instructed to enter a thaw point scope for each compound. instead than a individual temperature runing point. The ground for this direction is that polymers and unpure substance thaw over a scope of several grades. Based on the thaw point ranges for both substances. it is hard to distinguish the two based on its thaw point informations entirely. The scopes of the substances are near plenty to one another that 1 could reason for experimental mistake when showing the information as a solo placing belongings.

Based on these decisions. I do non believe the tetracosane is a pure substance because I observed the compound melt over a scope of grades Celsius. If both compounds in the mixture were composed of tetracosane. its thaw point would be theoretically. indistinguishable to the runing point of the original experiment. However. the runing point of the mixture was below that of the original informations. reenforcing the cognition that adding a derivative to a compound will take down its runing point.

During the experiment. heating the H2O excessively rapidly would make inaccurate informations. If the H2O is heated excessively rapidly. the thermometer may hold a difficult clip maintaining up with the temperate. therefore exposing an inaccurate measuring. It would be must harder to obtain an accurate scope. if this were the instance. as the substance may run faster than discernible. A molecule’s thaw point is brooding of its physical belongingss. Melting points disrupt intermolecular forces. distributing atoms over a greater surface country ; runing points do non impact covalent bonds. therefore are non chemical alterations.

At the decision of this experiment. I have determined that the molecular weight of the given molecules played a greater function in finding its thaw point. 1-tetradecanol. an intoxicant. contains the functional group –OH. This type of bond is referred to as a Hydrogen bond ; H bonds are much stronger than typical dipole-dipole bonds found in many ionic compounds. The molecular expression for tetracosane is C24H50. The molecule contains no functional group. so the intermolecular bonds are dispersion forces ; the weakest bond noted between atoms. Give this information sing mutual opposition and the molecular weights of the compound. it is easy to reason that the weight of the tetracosane caused it to hold a higher thaw point.

DecisionAt the decision of this experiment. I have a better apprehension of the significance of organic compound’s physical belongingss. More specifically. I have a erudite how liquescent points can help in the designation of a molecule. It is of import to retrieve that a molecules runing point entirely is frequently now plenty informations to correctly place the compound. This is why molecules are frequently melted utilizing derived functions. I have besides come to understand how a molecules mutual opposition and molecular weight can act upon its thaw point. It was apparent in this experiment that the heavier molecule withstood increased temperature longer. I was besides able to acknowledge how assorted compounds will change the thaw point of the pure substance. My apprehension of the information found in this lab will help in my surveies of organic chemical science as I become more accustomed to acknowledging molecules based on the belongingss they illustrate.


Fryhle. C. B. . & A ; Solomons. T. W. G. ( 2011 ) . Organic Chemistry ( 10th Ed ) . Hoboken. New jersey: John Wiley & A ; Sons Inc.

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