Essays

25. Repeat steps 17. to 24. two more times to produce three data for the de-ionised water of (about) 20°C.

The purpose of this experiment was to identify any possible relationship between salts and freezing point depression by testing their effects on the temperature of an ice cream mixture.

7. Why does this occur? It happened because the more concentrated it became it causes the molecules to move down.

2. The least precise measurement was the temperature but more specifically the freezing points of the solutions and solutes. Due to the freezing point only having two significant figures, the data is limited to two significant figures as well.

Purpose: The purpose of this laboratory was to gain an understanding of the differences between the freezing points of pure solvent to that of a solvent in a solution with a nonvolatile solute, and to compare the two.

The density of the solvent is = 0.784 kg/L and the specific gravity is 0.754.

Please be sure to follow all guidelines (number of sentences/showing all calculations) and to provide the correct metric units of measure. All questions are 5 points (1 point for sentence number /units).

44. Write reactions to show the dissociation into ions of the following substances when they dissolve in water:

Introduction: The experiment's goal was to determine the freezing point of a pure solvent and the freezing point depressions of two solutions. The freezing point and the freezing point depressions were determined by graphing the temperature of the pure solvent and two solutions as they cooled and observing when crystals first formed.

The assignments are cumulative, meaning that you will use the information from part #1 to answer part #2, and the information from part #2 to answer part #3. In order to help eliminate carry through error, I will post the solution to each part after the due date. It will be your responsibility to correct your answers (and your Excel spreadsheet) before moving on to the next part.

As stated in table 1 the molar mass of the unknown was found to be 79.07 g/mol. The true molar mass, obtained from the professor, was 60 g/mol. The experimental molar mass resulted in a 31.78% error. According to the moderately low percent error, the molar mass of the unknown was determined using its freezing point depression. The percent error achieved in this experiment is moderately low, but to determine accurate results it should be lower. A possible source of error could be not constantly and consistently stir the aqueous unknow solution. This would result in a lower spike in supercooling and could lead to a lower, less accurate freezing

The presence of a solute lowers the freezing point of a solution relative to that of the pure solvent. For example, pure water freezes at 0°C (32°F); if one dissolves 10 grams (0.35 ounces) of sodium chloride (table salt) in 100 grams (3.53 ounces) of water, the freezing point goes down to −5.9°C (21.4°F). If one uses sucrose (table sugar) instead of sodium chloride, 10 grams (0.35 ounces) in 100 grams (3.53 ounces) of water gives a solution with a freezing point of

Answer these questions using complete sentences where appropriate, and all assignments should be typed with correct grammar.

100 kmol/h of a mixture consisting of the following three components and their respective mole fractions:

b) How many moles of O2 must be added to a mixture of 2.8 gm of CO and 3.2 gram of SO2 present in 7 liters flask at 25oC to bring the total pressure to 1.5 atm?