Concentrate on Chemistry!

With lab partner Fabiana B.

Purpose: To learn from solutions and look closer at dissolved substances in solutions.

Hypothesis: Predictions: 9 tablespoons of sugar and 9 tablespoons of salt.

Materials:

• Sugar, C12H22O11 (60 g)
• Salt, NaCl       (60 g)
• Water, H2O (200 mL)
• 250 mL beakers (2)
• Balance
• Stirring Rod
• 2 spatulas or plastic spoons
• 2 green or red gummy bears.

Safety:

Sugar can be slightly hazardous after prolonged exposure to skin, eyes, and if inhaled.

(Material Safety Data Sheet, Sugar)

Salt can be irritant to skin, eyes, and if inhaled.  
(Material Safety Data Sheet, NaCl)

Procedure:

1. Firstly, make a prediction about how much (in grams) sugar can be dissolved in 100 mL of water. Do the same for the salt.
2. Find the combined mass of a beaker with 100 mL of water in it.
3. Then, add sugar to the water until the water will no longer dissolve any more sugar. Enter data into the table about how much sugar it took to saturate the water.
4. Repeat the steps using fresh water and table salt.

Part II

1. Put a gummy bear into the sugar solution overnight and record observations.

Background:

This lab studies the point at which water is saturated with sugar/ salt. Saturation occurs when the solute (in this lab, water) can dissolve no more solvent (in this case, sugar or salt). Concentration is how much solute there is per a solution.

Data:

_________________________________________________________________________________

Solid Solute Volume of Mass of Mass of Volume of

water (mL) water and solution and solution (mL)

beaker (g) beaker (g)

_________________________________________________________________________________

Sugar 100 113.08 221 165

C12H22O11

_________________________________________________________________________________

Salt  100 113.23 133.1 100

NaCl

_________________________________________________________________________________

Calculations

1)To find mass of solid added:

Mass of solution and beaker - Mass or water and beaker= Mass of solid added

Sugar: 221.0-113.08= 107.92

Salt: 133.1-113.23= 19.87

2) To find mass of solid per liter of solution:

Mass of solid added/ (volume of solution (mL)/ 1000, to convert to liters)

107.92/(165/1000)= 654.06 g/L

3) To find moles of solid added (mol)

(Mass of solid added) (1 mol)/ (mohler mass)= Moles of solid added

107.92/ 342.11= .315 moles

4) To find the Moles of dissolved solid/ liter:

Moles of solid added/ volume of solution (L)

.315/ .165= 1.90 moles/Liter

_________________________________________________________________________________

Mass of                        Mass of                             Moles of                          Moles of

solid added dissolved solid solid added dissolved solid

(g) per liter of solution (mol) per liter of solution

(g/L) (mol/L)

_________________________________________________________________________________

Sugar: 107.92               654.06                              .315                                     1.90

________________________________________________________________________________

Salt:    19.87                 198.7                                .339                                     3.39         

________________________________________________________________________________

Part II:

1) The bears in the solution and their reaction to the solutions in which they are placed in vary.

A) This bear was in water, and expanded greatly and held more water than any other solution. This is because in an unsaturated solution, the water is trying to absorb more and is moving throughout the gummy bear to expand it.

B) This is a mostly water solution, however, with some sugar and this has an impact on the size of the gummy bear, the more saturated the sugar solution becomes, the less the water will expand the gummy bear because there is less water to run through the gummy bear. 

C) This is a further degree of letter B in that there is more sugar in the C solution than there is in either A or B and this prevents the gummy bear's expansion. This gummy bear is smaller than either A or B because of the higher concentration of sugar. 

D) This is a more though not completely saturated solution. The gummy bear is even more compressed than either A, B, or C and this is due to the high sugar content of the water. 

E) This gummy bear has hardly expanded at all and this is to due, as already outlined, to saturation. The solution in which the gummy bear is in is a corn syrup solution. It cannot hold any more sugar. and there isn't enough water to move through the gummy bear and expand it.

2) If it was sugar moving into and through the bears, the sugar solution would be the most inflated and the water solution would have the most compressed gummy bears. 

3) The gummy bear left overnight shrunk, like letter E solution. This shows that the solution is saturated because the gummy bear was not only heavier than the solution and sunk, it also didn't expand in size. 

Discussion of Error: In this lab, there was an error in which part of the salt solution was spilled before the volume could be measured for the second time. Thus, the reason for only 100 mL being recorded for the volume of the salt solution.

Conclusion: The original hypothesis was wrong because the water was able to hold 20 teaspoons of sugar and the salt water saturated at 12 teaspoons. The purpose was carried out in that saturation and the process of saturating was witnessed.

Questions:

1) Because the NaCl Molecule is a lot smaller than a sugar molecule, a lot more mols of NaCl were able to fit into one liter. With the dissolved solid/ liter, the number is much greater because the sugar solution was able to hold and dissolve more than the salt solution could dissolve of salt.

2) The volume is different because in the lab, matter was added to the water, it is no longer just a water solution but a water and sugar/ salt solution. This extra sugar/ salt takes up more space than the water did alone.

3) 12 percent of 2.3 (g) =.27 
.27/ .001= 270
(.27)/ (342.119)
.000789/ .001
The gummy bears contain a concentration of .789 mols of sugar per liter.

Citations:

Material Safety Data Sheet. Sucrose. thesciencelab.com. Retrieved from:

http://www.sciencelab.com/msds.php?msdsId=9927285.

Material Safety Data Sheet. Table Salt, NaCl. thesciencelab.com. Retrieved from: http://www.sciencelab.com/msds.php?msdsId=9927593