The purpose is to use the mole relationships to prove the validity of the balanced chemical equation and that the final product of the experiment would confirm the balanced equation. The hypothesis made is that the experiment would in fact confirm the balanced equation. This is because, by balancing the equation two products that do exist are hypothetically formed. By the end of this experiment it will be seen whether the products calcium carbonate and sodium chloride will be made upon mixing calcium chloride and sodium carbonate together.
The dependent variables are the amount and the chemical composition of the product formed and the independent variables are the individual amounts of deionized water, calcium chloride and sodium carbonate. Therefore, if calcium chloride and sodium carbonate are mixed together, then the reaction will produce calcium carbonate salt and sodium chloride.
* Stirring rod
* Electronic balance
* Fine filter paper
* Deionized water
* 2 small beakers
* Sodium carbonate
* Erlenmeyer flask
* Graduated cylinder
* Calcium chloride
* Safety glasses
1. The groups name was marked in pencil on the rim of the filter paper.
2. The mass of the filter paper was measured and recorded.
3. A clean dry small beaker was put on the electronic balance and was tarred. 2.138 grams of sodium carbonate crystals were added and the exact mass was recorded.
4. A different beaker was then put on the electronic balance and was tarred. 1.040 grams of calcium chloride was added to and the exact mass was recorded.
5. Approximately 25 mL of deionized water was added separately to each of the beakers. Each beaker was stirred with different ends of a stir rod until the solids were dissolved.
6. The calcium chloride solution was poured into the sodium carbonate solution.
7. The funnel was rested in a tall Erlenmeyer flask and the liquid was poured through into the filter paper which lined the inside of the funnel. This collected the solid.
8. Two separate 10 mL quantities of deionized water was poured through the filter paper.
9. The beakers and stir rods were cleaned and returned to their appropriate places.
10. When dried, the mass of the filter paper and soil was measured and recorded and discarded into the garbage.
Final Substance (Na2CO3 + CaCl2 )
* When mixed with water, foam appeared at the side and the surface of the solution
* There was also a white flaky substance that formed
* When mixed with water, the solution fogged up with foamy substance at the sides of the solution
* Tiny bubble like substance also formed at the side
Final Substance (Na2CO3 + CaCl2 )
* When the two substances mixed together, a white powdery precipitate was formed.
* The flakes of powder were easily broken down.
The initial hypothesis stated can now be proved correct as after completing the experiment, the statement, which stated that the experiment would prove the balanced chemical equation true. As in the balanced equation CaCO3 was formed, this is in fact calcium carbonate, which is the salt that was produced.
It is known that a chemical reaction took place because a precipitate was formed, one of the indications of a chemical equation. Also, this is a double displacement reaction.
The information given by coefficients in a balanced equation can be understood to represent the relative number of molecules of that substance and as the relative number of moles involved in the reaction. Equations must be balanced because: Law of Conservation of Matter: Atoms can be neither created nor destroyed in an ordinary chemical reaction, so there must be the same number of atoms on both sides of the equation. The mass of all the reactants (the substances going into a reaction) must equal the mass of the products (the substances produced by the reaction).
By using the percent yield, the success of the experiment can be determined. The higher the number of the percent yield (closer to 100%) is an indication that the experiment was more successful. The percent yield of this experiment is 99.68% – 100.32%, which indicates that the reaction was successful, but the change of 0.32% is also to be noted. This change may have been caused because of incorrect mass data.
Possible errors that could have occurred involve an inaccurate measure in mass of the final substance. When pouring the calcium chloride into the sodium carbonate, there was a residue left in the beaker that held the calcium chloride therefore not all of the substance was poured into the sodium carbonate. This also occurred when the final solution was poured through the filter paper. This would have led to a change in the mass data of the initial products to produce the insoluble calcium carbonate salt.
Another error that could have occurred includes the fact that the product produced was kept overnight exposed to dust particles which may have mixed with the product and changed the mass data or the chemical composition of it. Also, there may have been impurities within the instruments used to perform the experiment. As other classes also use the same instruments, it can be determined how well they were cleaned and what chemical residue may have been left on the instruments.
Modifications to the procedure of this lab that can lead to fewer errors include and more reliable results would be to check the utensils used for the experiment very well and to clean them with a cleaning agent to cancel out the possibilities of chemical residues left on them. Also, leaving the filter paper with the product in an airtight container or other vessel that would allow for steady temperatures and not let any substances in or out of the vessel.