Analysis: Post-Lab Calculations And Analysis

Conclusion – The main idea of this experiment is that if you have the reactants of a double replacement reaction that you should be able to find out several things. First, you can figure out the products from switching the positive ion with the other positive ion. Once you have found the products you can determine the phase of matter they are in from Table F and H. Finally, you can also determine whether the reaction went to completion or not. The observations and data above leads me to believe that our experiment is valid. We were very careful and observant of the directions that needed to be taken. Once source of error could have been that certain substances were placed in the wrong wells, causing your data to stray from the correct information. One way this experiment could be applied to a real life situation is he residue in the bottom of a glass in your bathroom. There is stuff dissolved in water, and any trace of water left in a glass will eventually evaporate and leave the residue.

The Congress authorized the amount of copper in a penny after 1982 to be 2.5% by mass. The mean value found from this lab was 3.018%. There were no discernable variations based off of the penny’s apperance or mint date. The value reached from this lab is significantly different from the authorized copper content.

The control portion of a petri dish was used but we did not test to see if reacted with the hydrogen peroxide, so there was technically no control in this case.

The data gathered and calculated in the experiment accurately portrayed the way the reactions would have taken place. The chloride analysis was a little bit off from other groups due to the fact that our AgCl was in clumps, creating less surface area, thus our product took longer to burn and may not have burned correctly compared to other groups; yet there are several experimental factors that could have caused us to have different results than other groups, i.e. different measurements for samples. Our sources of error could have included eye measurement error, timing of set solutions error, measurement errors, and small calculation errors. Among other variables, the calibration of the analytical balance and spectrophotometer could have

10. As described in problem 7, a procedure was developed to determine the percent zinc in post 1982 pennies. In that procedure 50 ml of an HCl was used to react (dissolve) all of the zinc in the penny. To ensure complete reaction, the solution contains twice as many moles of HCl that is actually needed. To determine the percent zinc in the penny, the excess (unreacted) HCl was titrated with NaOH. Determine the concentration of NaOH needed if you want to use approximately 25 mL of NaOH to titrate the excess HCl.

B2.Place a few crystals of copper(II)sulfate pentahydrate in a test tube. Clamp the tube and heat in a horizontal position. One of the products is copper(II)sulfate. What is the other one? This decomposition reaction is easily reversible. Add a dropperful of water to the tube when it cools. Record what happens.

-If the copper metal is submerged in the silver nitrate solution then in reaction, a pure, solid (Ag) silver product is created with an excess of (Cu (NO3)2) copper (II) aqueous liquid because a single displacement reaction occurs where the balance equation is then

3.What was your prediction about the results of each factor tested in your two lab procedures? Explain your predictions based on your knowledge of the dissolving process, collision theory, and reaction rates.

3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds.

4. Calculate the ratio of moles of copper produced to moles of iron used. Ratio 2 : 1

The hypothesis is correct. Potassium chloride mixed with silver nitrate creates a white precipitate. Barium

Purpose: The purpose of this experiment was to observe the many physical and chemical properties of copper as it undergoes a series of chemical reactions. Throughout this process, one would also need to acknowledge that even though the law of conservation of matter/mass suggests that one should expect to recover the same amount of copper as one started with, inevitable sources of error alter the results and produce different outcomes. The possible sources of error that led to a gain or loss in copper are demonstrated in the calculation of percent yield (percent yield= (actual yield/theoretical yield) x 100.

5. Part B.1. Eliseo couldn't find the 6 M HCl and so used 6 M HNO3 for testing the metals instead. His logic? Both are strong acids. Explain how the results of the experiment would have been different.

These reactions can be seen from just a little bit of reaction all the way up to a complete change of the entire sample tested. Some samples of those tested in this experiment which showed the chemical reaction were the baking soda/ammonia mixture, the Epson salt and baking soda mixture as well as the food coloring mixed with the baking soda and bleach. 2. Which reactions, if any, do you believe showed no evidence of chemical change? Justify your reasoning.

A chemical reaction is when substances (reactants) change into other substances (products). The five general types of chemical reactions are synthesis (also known as direct combination), decomposition, single replacement (also known as single displacement), double replacement (also known as double displacement), and combustion. In this lab, the five general types of chemical reactions were conducted and observations were taken before, during, and after the reaction. Then the reactants and observations were used to determine the products to form a balanced chemical equation. The purpose of this lab was to learn and answer the question: How can observations be used to determine the identity of substances produced in a chemical reaction?