Please answer questions 1-4 on the Pre-Lab Assignment Limiting Reactants: The Re
ID: 535354 • Letter: P
Question
Please answer questions 1-4 on the Pre-Lab Assignment Limiting Reactants: The Reaction of Zinc with Iodine Introduction In this experiment, you will observe the direct reaction between two elements, zinc and iodine. This reaction is a synthesis or combination reaction. One of the reactants will be present in excess, while the other will be the limiting reactant. The reaction will stop when the supply of the limiting reactant is exhausted. To determine how much of the other reactant was involved in the reaction, the mass of any unreacted reagent is subtracted from the amount initially present. If the experiment is done carefully, the mass of the reactants will be compared to the mass of the products, and Law of Conservation of Mass will be confirmed. There are many steps involved in the synthesis reaction performed in this experiment. With the increasing number of steps, the likelihood of making an error increases. Each of these errors will affect the percent yield at the end of the experiment. While percent yield would be 100% if the experiment is done perfectly, it is rarely possible to complete an entire procedure without any errors. Percent yield can easily be assessed using the following equation. A value near 100% indicates an accurate result. Values can be higher or lower than 100%. Percent Yield = Actual Mass/Calculated Mass (Calculated mass is also called theoretical mass.) Since the masses and identities of the reactants are known, the empirical formula of the final product can be determined. Based on the behavior of zinc and iodine, the empirical formula can be predicted, but the data in this experiment will make it possible to see if the results match the predictions. Prelaboratory assignment Two reagents are being used in this experiment with which you must be extremely careful. Which reagents are they? What safety precautions must be taken to account for this? Describe the method of weighing by difference. What is the advantage of weighing by difference over using a piece of weighing paper on the balance to determine the mass of a reactant used? If the instructions ask you to collect a mass of sample of 1.5 plusminus 0.1g, what is the smallest mass that should be obtained? Largest Mass? Write the balanced chemical equation for the reaction of elemental zinc with elemental iodine. (Remember that some elements are diatomic). Objectives To perform a synthesis reaction between samples of two elements. To determine the percent yield of a synthesis reaction. To identify and assess the errors made during a synthesis reaction and explain how these errors affect overall yield.Explanation / Answer
Zn + I2 --> ZnI2
Reaction type = Synthesis
Prelab
1. I2 is very corrosive, toxic and irritant. Care must be taken to handle this reagent properly. Use proper clothing, cloves, working in fume hood when handling this chemical.
2. Weighing by difference ensures minimal error and gives more accurate results as opposed to weighing by papaer and tare afterwards wherein even a slight change in the environment would result in greater error.
3. smallest mass 1.4 g is to be obtained with given information.
4. Equation,
Zn + I2 ---> ZnI2