Joe Schmoe Period 3 March 8, 2013 Lab Report: empirical formula of Zinc Chloride (ZnCl) * Purpose The purpose of this experiment was to learn how to determine the empirical formula. Empirical means “based on experimental evidence. ” * Experimental Design The reaction that occurred was the reaction of the elements Zinc (Zn) and Chloride (Cl) by mixing a piece(s) of Zinc and 50mL of Hydrochloric Acid (HCl).
The amount of Zinc was determined to be between 1. 00g and 1. 25g. As the reaction occurred there was still water left in the beaker.
In order to remove the water we heated the beaker to evaporate it. The Zinc Chloride then formed as a solid white substance. * Observations As the Zinc and Hydrochloric Acid reacted, bubbling and fizzing occurred. The water became cloudy as the Zinc began to decompose and break apart. The Hydrogen in the Hydrochloric Acid was being released as vapors. * Data & Evaluation The mass of our beaker was 58. 78g. Our piece of Zinc was massed at 1. 24g. Therefore, the combined mass of the beaker and Zinc was 60. 02g.
After the reaction and heating, the combined mass of the Zinc Chloride and the beaker was 61. 39g. We heated the substance again to remove any excess water. The combined mass of the beaker and Zinc Chloride was then 61. 36g. To find the mass of the reacted Zinc Chloride we subtracted the mass of the beaker (58. 78g) from the total and the mass of the Zinc Chloride came out to be 2. 58g. Subtracting the mass of the Zinc (1. 24g) from the Zinc Chloride mass, we found the mass of just the Chloride was 1. 34g. * Conclusion
The Essay on Dialysis Bag Glucose Beaker Water
Diffusion LabProblemWill starch, water, glucose, iodine or a combination of the above diffuse across the membrane of the dialysis bag causing the bag to either expand or shrivel? Hypothesis & Strategy I believe that the smaller molecules, such as glucose and water will diffuse through the dialysis bag's membrane causing it to expand, due to the concentration gradient. I would test this ...
To find the Empirical formula we first needed to find the number of moles of each element per the mass of each element. You must divide the obtained mass of an element by the atomic weight of that element. 1. 24g Zn ? 1 mol Zn65. 4g Zn= . 018 mol Zn 65. 4g represents the atomic weight of the Zinc on the periodic table 1. 34g Cl ? 1 mol Cl35. 5g Cl= . 037 mol Cl .018 mol Zn. 018 mol Zn=1 . 037molCl. 018molZn=2. 05 The empirical formula of Zinc Chloride is ZnCl2. 05. The accepted formula for Zinc Chloride is ZnCl2.
Our answer may be slightly off because of there may be leftover water that was not evaporated. As a result, the mass of the Chlorine would be higher and that would make the moles of Chlorine higher, causing the ratio of Chlorine to Zinc to be slightly higher than 2. Another error that could have been made is if the Zinc Chloride was heated too much and it began to release chlorine. Do so would make the mass of chlorine decrease, which would make the moles of Chlorine decrease and the ration of Chlorine to Zinc be slightly lower than 2.
