Background of the experiment
When a gm of Potassium Nitrate is deposited in a millilitre of H2O the clip taken for the substance to fade out is called rate of solubility of the salt. This is measured by and large by utilizing experimental methods. The solubility has been found to be affected by many factors such as mutual opposition of the dissolver, mass of the solute, Temperature of the mixture etc. Hence to happen the relationship between temperature and rate of solubility of Potassium Nitrate in H2O this experiment has been designed
Hypothesis
The addition in temperature of the H2O makes the ions of Potassium Nitrate ( K+ and NO3- ) addition Kinetic Energy which increases the velocity with which the ions move between the solution and its solid province easy this increases the rate of solubility of the salt ( KNO3 ) in H2O.
Harmonizing to the 2nd jurisprudence of thermodynamics, the atoms shifts from an ordered province to more broken province this makes the solution more spread if the temperature increases.
As the temperature of H2O additions, the atoms of solid Potassium Nitrate, KNO3, which are absorbing energy from its surrounding, get down traveling more easy between the solution and its solid province this can as, harmonizing to the 2nd jurisprudence of thermodynamics, the atoms will switch to the more broken province hence, more extremely spread solution province. From this a anticipation can be made that as the temperature of a KNO3 and H2O mixture additions, so the solubility of the KNO3 will besides increase.
Variables
Independent variable:
Temperature of the mixture is changed by utilizing a icebox or a Bunsen burner mensurating it with a digital thermometer for the best alteration in temperature.
Dependent variable:
the dependant variable will be the rate of solubility of Potassium Nitrate in H2O that will be measured at different temperatures
Control variables:
The volume of distilled H2O used to fade out Potassium Nitrate in each beaker ; this is controlled by taking changeless volume of distilled H2O each trail by mensurating it with a mensurating cylinder.
Mass of Potassium Nitrate deposited into each beaker. The mass of the Potassium Nitrate dissolved is controlled by fade outing changeless mass of Potassium Nitrate by mensurating it with a digital balance.
The volume of Potassium Nitrate solution taken by the syringe from the different beakers to mensurate the rate of solubility. The volume of Potassium Nitrate solution taken by syringe is controlled by utilizing a syringe with a installation of mensurating the volume of the solution taken so maintaining the volume taken same in all the panpipes taken.
Weight of each 50ml beaker used. This is controlled by taking indistinguishable beakers each clip
Methods and Reasons to command the variables
The mass of Potassium Nitrate and the volume of distilled H2O introduced into each beaker should be recorded in order to let the experimenter to find the molar concentration of Potassium Nitrate in H2O. Since the same sum of H2O and Potassium Nitrate are used in each beaker throughout the whole experiment, these variables are the least likely to be the beginnings of mistakes.
All 6 solutions will be supersaturated in Potassium Nitrate. If the solutions were non supersaturated, an addition in solubility will non be noticeable.
In order for all the solutions be subjected to the same experimental conditions, the same sum of clip dedicated for stirring should be the same in all 6 100ml beakers.
The usage of different panpipes for the extraction of the Potassium Nitrate and distilled H2O solution from each beaker avoids the possibility of contradiction in the instance where the same syringe was used in all 6 beakers.
The usage of different panpipes for the extraction of the Potassium Nitrate and distilled H2O solution from each beaker avoids the possibility of contradiction in the instance where the same syringe was used in all 6 beakers.
The acerate leaf of the syringe should be placed at the center between the surface of the solution and the underside of the beaker upon extraction. This is because of it were placed at the surface of the solution some air partiNO3es might come in the syringe, and if it were placed at the underside of the beaker some dissoluble partiNO3es might be extracted, thereby taking to an addition in the existent concentration of the dissolved salt.
The weight of each 50ml beaker ( used for weighing the mass of dissolved Potassium Nitrate after the vaporization of H2O ) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a beginning of mistake.
In order to minimise mistakes and to topographic point ” the solutions in the same environment, the same volume should be extracted from each solution utilizing the panpipes.
After heating the extracted solution in the 50ml beaker for weighing intents, some of the H2O might distill back into the liquid province ( in the signifier droplets ) , thereby taking to an addition in the deliberate weight of Potassium Nitrate. Therefore after vaporization has occurred and while the 50ml beaker is still hot, the beaker should be instantly weighed.
Apparatus:
- Six Panpipes
- One Heating home base
- Digital Thermometer
- Water at 0A°C
- Bunsen Burner
- Six clearly labeled 50ml Beakers
- One Digital Balance
- Six Stiring Rods
- Distilled Water
- Six clearly labeled 100ml Beaker
Procedure:
- Weigh each of the 50ml beakers labeled 1, 2, 3, 4, 5 and 6 and enter their multitudes.
- Introduce 100ml of distilled H2O into beakers 1 through 6.
- Beakers 1, 2, 3, 4, 5 and 6 are held at 0A°C, 10A°C, 20A°C, 30A°C, 40A°C and 50A°C severally.
- Dissolve 50 gms of Potassium Nitrate into each beaker by utilizing a stirring rod. The stirring in all 6 beakers should last 10 proceedingss.
- Insert the syringe at the center between the solution ‘s surface and the underside of the beaker and extract 40ml as such from each solution.
- Push the contents of each syringe incorporating samples from the solutions in beakers 1, 2, 3, 4, 5 and 6 into the 50ml beakers labeled 1, 2, 3, 4, 5 and 6 severally.
- Heat each of the 50 milliliter beakers until complete vaporization of the H2O occurs, and so instantly put each beaker on the balance and record the mass.
Data Collection
By deducting from the combined mass of ( 1 ) the salt residue from the evaporated extracted solution ( M1 ) in the 50 milliliter beaker and the mass of the corresponding 50ml beaker ( M2 ) , the mass of the salt ( m0 ) dissolved in the Sample solution can be obtained.
m0= m2- M1
The figure of moles can be calculated, by utilizing the expression
n= m0/MM,
Where m0 is the mass of the salt obtained in the sample solution and MM is the molar mass of the salt which is 58.44g mol-1
The figure of moles is so divided by the volume of the extracted sample ( 40ml ) . The obtained concentration is so multiplied by a factor of 5, in order to acquire the concentration of the initial solution.
As the figure of moles dissolved is calculated the rate of solubility can be estimated. By the expression
Rate of Solubility ( s ) = Number of moles in salt residue ( n ) ? Time it is at that place in the liquid ( T )
The tabular array for the above process:
S.no Temperature of the mixture
Mass of Salt residue from the evaporated extracted Solution ( g )
Number of Moles of the salt residue ( mol )
The concentration of initial Solution ( mol dm-3 )
This is harmonizing to the hypothesis formed in the starting of the experiment.
A graph can be drawn as follows for the fluctuation of the rate of solubility with temperature of the mixture.
Number of moles of the salt residue
Temperature of the mixtureThe gradient of the below graph shows the fluctuation of the rate of solubility with temperature of the mixture
The point to be noted here is that the graph is drawn by the theory from the hypothesis therefore it shows that the Temperature of the mixture is straight relative to amount of salt dissolved in H2O.
