The purpose of this lab is to focus on how to make zinc iodide in a different way using compounds instead of elements, which are barium iodide and zinc sulfate. We will see if the reaction between these two compounds will occur and make a prediction by writing a chemical equation. The procedures for this lab are to place a small test tube inside a 50mL beaker and weigh it. Then, using a spatula, add 0.45±0.03 g of zinc sulfate heptahydrate into the small test tube and record the mass. After that, dissolve the sample in 2 mL of deionized water and shake the test tube for 1 to 1 ½ minutes to dissolve the solid.
Hydrate Lab The purpose of this lab is to analyze the percent water in a crystalline hydrate and to indentify the hydrate from a list of possible unknowns. The solid hydrate will be heated to remove the water, and the percent can be found by measuring the mass of the solid before and after heating. The hydrate will be indentified by comparing the percent water in the hydrate with the percent water calculated for the possible unknown. Before the lab there are pre-lab questions: 1. Describe the three general safety rules for working with a Bunsen burner.
Experiments and Data See Attached (Page 86-91 of Lab Manual) Analysis Per the lab manual’s instructions, 1 g of CaCl2 + 2H20 was measured out and added to 25 mL of distilled water; the water had to be distilled to remove the impurities found in merely filtered water, and would therefore skew the results. This formed our first solution, calcium chloride. What we didn’t know going into the experiment was how much of the Na2CO3 would be needed to complete the experiment, so using stoichiometry we determined that the mass of the crystals needed to complete the reaction was around .68 g of Na2CO3. This was mixed with another 25 mL of distilled water, forming our sodium carbonate solution. The two solutions were mixed, forming a precipitate called calcium carbonate.
Conclusion:The purpose of this lab is to prepare and purify a fuel, ethanol C2H5OH. We learned to do so by the process of fermentation, and distillation. Over the course of 2-3 weeks, we collected and analyzed the data for this lab. On day 1, we prepared our sugar-yeast solution which contained warm water, sugar, and yeast. With the help of the water, the yeast was then the reactant, then which was activated.
On-line Science Simulations - Marble Chip Student Worksheet When hydrochloric acid is added to calcium carbonate (marble chips) carbon dioxide is evolved. In the experiment shown, 21.6 g of calcium carbonate is added to 200 cm3 of hydrochloric acid. The number of chips can be varied but the total mass is always 21.6 g and the volume of acid is always 200 cm3 but the concentration can be varied. The apparatus is placed on a balance that has been zeroed so that it always shows the same initial mass at the start of the experiment. During the reaction, carbon dioxide is evolved and the mass decreases.
ABSTRACT In the “Density, Accuracy, Precision and Graphing” experiment, the purpose was to determine the density of water and the concentration of a saline solution as well as to compare the accuracy and precision of a graduated cylinder and a graduated pipet. Based on the instructions of the lab manual, Fundamentals of Chemistry, the experiment was performed in three parts, Part A: Density of Water-The density of water was calculated by measuring the mass of three different volumes: 10mL, 30mL and 50mL. Part B: Accuracy and Precision was performed using a 100mL beaker, 10mL graduated pipet and deionized water. The experiment was performed three times; each time, 10mL of water was added to the beaker and recalculated. Part C: Density of Sodium Chloride (NaCl) Solution, a sample of NaCl was obtained and measured using a 100mL beaker and a 10mL pipet to determine the concentration of the solution.
The length of time it took for each sample to freeze was recorded as shown below. Amount of salt added in grams (g) | Time it took for the water to freeze in minutes (min) | 0 | 48 | 1.25 | 69 | 2.50 | 76 | 3.70 | 90 | 5.0 | (Did not freeze during the time of the experiment) | Identify the independent and dependent variables in Carmen’s experiment. Do the experiment and results support the hypothesis as it was written? Explain your answer. Identify some specific changes that you would suggest for Carmen’s experiment in order to specifically test her hypothesis.
Glen Mings CHEMISTRY 1 SUMMER 1 Experiment 9 Report Submitted: June 28, 2015 Title: Determination of Water Hardness Using a Titrator Purpose: To find out how “hard” my tap water is; specifically the concentration of calcium carbonate in ppm, and compare it to the four classifications. Procedure: Using a titrator, I measured how much EDTA solution it took to bond all of the Ca2+ ions, which was determined when the EBT turned from purple to blue. And since the reaction is 1:1 stoichiometric, we can assume that the moles of EDTA used equal the moles of calcium ions. Data Collected: | Initial EDTA volume | Final EDTA volume | Total volume of EDTA used | Trial 1 | 7.0 ml | 6.6 ml | 0.4 ml | Trial 2 | 6.6 ml | 6.3 ml | 0.3 ml |
Data: Data Table 1 | | | Rubbing Alcohol Trial # | Boiling Point | Percent Error | 1 | 79.5 C | 3.52% | 2 | 84.0 C | 1.90% | 3 | 83.5 C | 1.30% | Data Table 2 | | | | Acetamide Trial # | Melting Point | Freezing Point | Percent Error (Melting Point) | 1 | 79.5 C | 57.5 C | 3.50% | 2 | 80.5 C | 59.5 C | 0.60% | 3 | 78.0 C | 61.0 C | 3.70% | Observations: It was observed that thermometer placement could affect the readings in the water bath. I ended up holding the test tube assembly to where the bottom of the test tube was not touching the bottom of the beaker to ensure better readings. Also, when substances recrystallize, I am not sure whether to take a reading when the substance has full crystallized or begun to so results could be fairly inaccurate. Questions: A. Why is it useful
Then allow test tubes to remain at various temperatures for 5minutes, remove the test tubes and add 2cm of catechol and shake to allow them mix. Finally the record the results. As temperature increases the rate of enzyme activity increases until it reaches its optimum point, in this graph the optimum point is 20-60 oC, This is the point where enzymes works best if temperature increases above the optimum point the rate of enzyme activity decreases until the point where the enzymes are denatured, the color intensity gets darker as temperature increases. Effects of pH on Enzyme Activity pH directly has an effect on the active site, and is therefore important to have proper pH,however high or lower ph. affect the enzyme activity, to get enzymes working there should be proper ph.