Proper techniques and procedures applied when determining the freezing point of the cyclohexane during the whole experimentation process and using the same tared balance all the way through the experiment since different inaccurate results may be obtained if different balances were used.
Both the boiling point elevation and the freezing point depression are proportional to the lowering of vapor pressure in a dilute solution. If two trials had been conducted, we would have been more confident in our results. If the thermometer had been digital, we believe that the temperature might have been more true to 6.
These values are correct for dilute solutions, where the dissociation of the compounds to form separately solvated ions is complete. Calculate the molality of the cetyl alcohol solution and use it to determine the value of the freezing point depression constant, kfp, for BHT.
We then use the freezing point depression to establish the molality of the new substance compared to water. The results of the freezing point of the pure water versus salt water were not as expected but this may be because of the tools used for this experiment.
To happen the molar mass of the unknown substance.
When a non-volatile does not vaporize solute mixes with the solvent, it lowers the vapor pressure of the solvent. A practical application of freezing point depression is using salt or magnesium chloride to melt the ice on the roads when it snows.
The fact that the freezing point of the solution kept decreasing as more solute was added supports the theory that colligative properties are affected by the amount of solute particles present and not by the chemical properties of the solute Beran, The osmotic pressure portion of this experiment began with soaking the dialysis bag in distilled water for 30 minutes.
The freezing point appeard to be 3? For the experiment, cyclohexane was used as a solvent, the solute remained unknown.
The solution changes the intermolecular forces. Plot the warming curves of pure cyclohexane. Discussion The molar mass of an unknown solute B was calculated to be We then weighed out 50g of salt, mixed it in mL of water, then added ice.
The ground it is approximative is because the thermometer used was non digital and can truly merely be used to the nearest.
This also raises the boiling point and lowers the freezing point. Techniques used in the experiment included: Determine molar mass 9. How would this hold affected the molar mass you found? Then the thermometer was inserted through the gum elastic stopper with the scaremonger around the base of the thermometer to about midway into the cyclohexane.
There are four types of colligative belongingss: Freezing point depression is colligative for most solutes since very few solutes dissolve appreciably in solid solvents.
Calculate the molar mass of the unknown substance 7. By the last trial performed, 0. In an aqueous solution of glucose, a portion of the surface area is occupied by nonvolatile glucose molecules rather than by volatile water molecules.
Then the thermometer was inserted through the rubber stopper with the stirrer around the base of the thermometer to about halfway into the cyclohexane.
Plot the warming curves of pure cyclohexane. Based on the graph depicted in figure 4, the freezing point of cyclohexane plus the unknown solute is 3. The trial tubing is so placed in the trial tubing holder and the trial tubing incorporating the cyclohexane is placed into the ice bath solution.
The boiling point of a pure solvent is increased by the addition of a non-volatile solute, and the elevation can be measured by ebullioscopy. We can view the system as having two competing equilibria: Molality is the solute concentration. The egg began to reduce in size and after 12 hours it was very close to its original size.
The following errors occurred when the above experiment was carried out. After one hour there was foam on top of the vinegar and there were many bubbles around the eggshell.The purpose of the experiment was to observe and measure the effect that solutes have on the freezing point of a solvent and to determine the molar mass of a solute.
Concepts explored throughout the conduction of the experiment included solutions, colligative properties, vapor pressure, freezing point, boiling point, molality and molar mass.
To happen the molar mass of the unknown substance. the colligative jurisprudence has to be used. The jurisprudence states that the freeze point and boiling point of a solution differ from those of the pure dissolver by sums that are straight relative to the molar concentration of the solute.
Colligative Properties & Osmotic Pressure Essay Sample. The ice bath might have been colder if a lot of salt was put on the ice, using the colligative property of freezing point depression. Questions: Part I: Colligative Properties A. Record your observations and your time and temperature data in tables.
What is its molecular mass.
Molar Mass by Freezing Point Depression OBJECTIVES: These properties are called COLLIGATIVE PROPERTIES, because they freezing point of the solution is determined from the graph by drawing two straight lines through the data points above and below the freezing point.
The temperature corresponding to the intersection of the two. Colligative Properties - Freezing-Point Depression and Molar Mass Colligative Properties – Freezing-Point Depression and Molar Mass Essay Sample The whole doc.
Start studying Lab #6 Colligative Properties: Freezing Point Depression and Molar Mass.
Learn vocabulary, terms, and more with flashcards, games, and other study tools.Download