Aim: My partner and I would like to investigate the solubility of different chemicals when placed into 25cm3 of water.
Hypothesis: I think that sugar will be the most soluble chemical. By this I mean that the sugar will be able to dissolve in the water even after 12 spatulas. The Calcium Carbonate will be the least soluble chemical and will not be able to dissolve early in the experiment at spatula number 3. I believe that sugar will be more soluble because, unlike calcium carbonate, physically sugar is not a powdery substance, and calcium carbonate is. Maybe their molecules have a stronger bond which would cause difficulty for the chemical to dissolve.
Independent Variable (input): Our independent variables will be: Calcium Carbonate, Calcium Sulphate, Sugar, and Sodium Chloride.
Dependent Variable (output): The mass of the solution, and the solubility of the solution.
Controlled Variables: Amount of water in 50cm3 measuring cylinder, volume of the chemical added each time, temperature of water.
Top hand balance(1)
Measuring cylinder 50cm3 (2, 1 per two chemicals [will wash after first use])
Measuring cylinder 10cm3 (1)
Glass stirring rod (1)
Pencil, ruler, eraser
First my partner and I will collect all of our materials needed. (Listed above)
Then we will select only one chemical to investigate first, and take 1cm3 of the chemical and place it into a 10cm3 measuring cylinder.
Next, We will fill the 50cm3 measuring cylinder with 25cm3 of water
After that, we will place the 1cm3 of our chosen chemical (already collected in step 2) in the 25cm3 of water, and agitate the solution. We will agitate the solution by mixing it with a glass-stirring rod. We will agitate the solution until all of the solution is dissolved.
Following the previous step, we will then record the spatula number. (Spatula number is the number of spatulas of the chemical placed in the water). By this step, we will be at spatula number 1.
Then we will proceed to repeat this routine (adding a spatula of the chemical and placing it in the water and agitating the solution) until the chemical has become a saturated solution, and cannot dissolve anymore.
When the chemical becomes a saturated solution, then my partner and I will note the spatula number (explained in step 5)
We will continue this procedure for all of our chemicals ( calcium carbonate, calcium sulphate, sugar, and sodium chloride)
Safety Hazards: (to be researched prior to experiment)
Sodium chloride: None
Copper Sulphate: hazardous to the environment, cannot be use in high concentration ( we did not use this chemical due to it’s safety hazards)
Calcium carbonate: Do not have contact with face or mouth, ensure one is wearing eye protection when using this chemical in any given experiment.
Calcium Sulphate: Do not have contact with face or mouth, ensure one is wearing eye protection when using this chemical in any given experiment.
Not colorless, immediately is white.
Could not dissolve at spatula number 1
Not colorless, immediately solution is murky white.
Could not dissolve at spatula number 1
Very clear and transparent.
Stopped dissolving at spatula number 32
At spatula number 5, solution starts to get less clear.
Couldn’t dissolve at spatula number 7.
Discussion & conclusion:
In the end my hypothesis was more or less correct. I had stated that I thought sugar would be able to dissolve after more than 12 spatulas of itself in water, however I was not specific as to how many spatulas. I also hypothesized that calcium carbonate would not be able to dissolve after 3 spatulas of itself in water. After the experiment I found that in my particular experiment, sugar did not become a saturated solution until spatula number 33, meaning that the last time that sugar could dissolve in 25cm3 was when there was 32 spatulas of sugar. This is because sugar can create very strong bonds with water molecules due to the many hydroxyl groups within the chemical.In addition, I found that calcium carbonate could not even dissolve when there was only one spatula of itself in 25cm3 of water. This was also true for Calcium Sulphate, for it could not even dissolve one spatula in 25cm3 of water. Sodium Chloride became a saturated solution after 6 spatulas, so at spatula number 7, it became a saturated solution and could no longer dissolve.
Modifications to original plan:
At first, the experiment of my partner and I was to investigate the solubility of calcium carbonate alone. However, Mrs. Lynch informed us that this experiment was lacking independent variables. So, my partner and I decided to alter our experiment by testing not only calcium carbonate, but calcium sulphate, sugar and sodium chloride in addition. Furthermore, my partner and I were going to measure the mass of our solutions, but we came to the conclusion that the mass was irrelevant and not necessary in our experiment.
I think our experiment was not entirely accurate. This is due to the fact that, with some chemicals we were not sure weather or not the solution was dissolved or not, and this judgment affected our data. Moreover, I myself would have liked to investigate the solubility of a variety of solutions rather than only four, but due to the time constraint and the materials available, this was not possible. So, if given the chance, I would do my experiment differently by being more accurate with our observations, and investigating more chemicals.
“question number 1496.” How things work. 26 Mar. 2007. 26 Mar. 2007