In the demo experiment, we placed 10 grams of Ammonium dichromate in the form of a solid before starting the experiment. When the experiment begins the Ammonium dichromate is burned up and then produces Chromium (III) oxide as a solid, Nitrogen gas and water in form of a gas. In the experiment, we combined Zinc Chloride and Sodium Sulfide in which both chemicals are aqueous. The result of the combination was Zinc Sulfide a solid and Sodium Chloride an aqueous solution. In the alternate experiment, we combined Lead (II) Nitrate and Potassium Iodide in which both chemicals are aqueous. The result of the combination was Lead (II) Iodide and Potassium Nitrate.
To see a chemical at a microscopic level you would need to use a microscope versus the
The way we would expect to observe this context in the experiment would be by seeing the reaction of adding chemicals together and separating the chemicals to see if chemicals were destroyed, created or neither. The type of chemical reactions performed were that the same amount of mass in the reactants are the same amount of mass in the products. The most important component of a reaction of this type is to do the experiment process correctly to achieve the results meant. Using the properties of the reactants and products involved, predict the outcome of the reaction and describe the methods used to successfully perform the experiment. Based on our data the law of mass conservation was observed through the experiments containing ZnCl2(aq) + Na2S(aq) and Pb(NO3)2(aq) + 2 KI(aq). We gained mass after mixing the chemicals and separating the chemicals for both experiments. In the first experiment the difference in the amount mass from the initial mass was 0.46 g and in the second experiment there was a difference in the amount mass from the initial mass which was 0.75 g.
In the demo experiment, the chemical reaction created was the release of nitrogen gas and H2O gas. In the experiment, the chemical reaction created was the formation of a solid ZnS and an aqueous sodium chloride. In the alternative experiment, the chemical reaction created was of
The molecular equation is a balanced chemical equation while the total ionic equation is done by separating all aqueous solutions to get each ionic number. If a solution is not aqueous you will not be able to separate them. To find the net ionic equation you will cross out like terms from both sides of the chemical equation. For the demo experiment, the molecular equation is (NH4)2Cr2O7(s) ——> Cr2O3(s) + N2(g) + 4H2O(g) which is balanced. The total ionic equation and net ionic equation is the same as the molecular equation. For the experiment, the molecular equation is ZnCl2(aq) + Na2S(aq) ——> ZnS(s) + 2NaCl(aq) which is balanced. The total ionic equation is Zn2+(aq) + 2Cl-(aq) + 2Na+(aq)+S2-(aq) ——> ZnS(s)+ 2Na+(aq) + 2Cl-(aq). While the net ionic equation is Zn2+(aq) + S2-(aq) ——> ZnS(s). For the alternative experiment, the molecular equation is Pb(NO3)2(aq) + 2 KI(aq) ——> PbI2(s) + 2KNO3(aq) which is balanced. The total ionic equation is Pb2+(aq) + 2NO3-(aq) + 2K+ + 2I-(aq) ——> PbI2(s) + 2K+(aq) + 2NO-3(aq). The net ionic equation is Pb2+(aq) + 2I-(aq) ——> PbI2(s). The problem that I am working with on these equations is stoichiometry. To solve this problem the only thing you have to do is look at the coefficient for each solution on both sides of the equation to see if the same amount per element is equal to each other.
The purpose of this experiment is to use our knowledge from previous experiments to determine the theoretical, actual, and percent yields of the lead chromate from the reaction of solutions of potassium chromate and lead nitrate (Lab Guide pg. 83).
One of the best methods for determining mass in chemistry is gravimetric analysis (Lab Handout). It is essentially using the the mass of the product to figure out the original mass that we are looking for. Thus the purpose of our experiment was to compare the final mass in our reaction to the initial mass and determine the change in mass.
To complete this lab several chemicals must be measured and transferred to test tubes. First 5.0 mL of 0.200 M Fe(NO3)3 must be diluted to a total volume of 50 mL in a flask. Next 0.0020 M SCN–. This solution is then added to 4 test tubes in 1 mm increments. Each test tube is then put in to
The details with respect to each of these items are discussed in the following sections. All experiments were based on the ability of the method to collect and analyze a 15-L air sample for each concentration tested. The sample preparation and analytical technique used during the method evaluation follow that described in reference 9.4. A revised method (9.1.) is also available.
“A chemical reaction is a change that makes at least one new substance,” according to Richard Spilsbury (2014, p. 8) A physical reaction is when you mix two or more substances and those substances stay the same. This experiment demonstrates a physical reaction called ‘nucleation.’ The rough surface of the Mentos and the carbon dioxide inside the soda combine together to make the soda explode! This is not a chemical reaction because we do not make a new substance. “In physical changes, the original substances do not change chemically. For example, you can dissolve salt in water to make salty solution,” according to Richard Spilsbury (2014, p. 13). In this case, you still have salt and water, not a new product. With Diet Coke and Mentos, you still have these two substances in a much messier form, but you do not have a new
After the solution was stirred, the solution turned into a mustard yellow color. When the luminol was dissolved into NaOH the solution turns a dark brown color. After the water was added into stock solution A, the color appeared medium brown. Following this, after the potassium ferrycyanide and hydrogen peroxide were mixed, stock solution B was made and appeared a yellow color. When stock solution B was diluted with water the resulting solution B appeared a to be a light yellow. Finally, after diluted solution A was added to solution B in a dark room the appearance of the solution was a glowing blue
For the first trial, 2 dry evaporating dishes were weighed on the balance, and their masses were recorded. The first dish was 71.74 grams by mass, while the second dish was 52.03 grams by mass. We added 2 grams of unknown mixture to the first evaporating dish, and we weighted it on the balance and recorded its mass. The mass of this dish was 74.74g. Then, the first evaporating dish was put on the clay triangle using crucible tongs on the Bunsen burner in the hood area. The mixture was heated, and there was a gas that was produced which was NH4CL. After the NH4CL was removed, we took the evaporating dish using tongs and it was left to allow it to cool. After the dish was cooled down, the dish was placed on the balance and weighted again after heating (McHugh 46).
Total ionic- Na+(aq) + OH-(aq) + H+(aq) + Cl-(aq) → Na+(aq) + Cl-(aq) + H2O(l) (Eq. 10)
...clear reaction at all. Some think that the process is merely a chemical reaction not yet understood by today’s laws of chemistry. This presents numerous gray areas in the understanding of the reactions taking place in the experiments. If indeed it is a chemical reaction then there is some flaw in our understanding of chemical reactions. The lack of nuclear byproducts when in theory there should be lends strong credence to this belief though. Only continued experimentation and new exploration will help explain the mystery.
In A3 the clear silver nitrate became dense and concentrated when hydrochloric acid was added. In A4 the Zinc became cloudy and grey. Bubbles continued to release sporadically.
Before beginning the experiment observe and record the physical appearance of all the chemicals used in the experiment. First write a balanced chemical equation that has Zinc iodide as product when Barium iodide and zinc sulfate are used. To begin today’s lab, weigh a small test tube on a scale that goes to the hundredths place. Using a clean spatula add .45 g + .03 grams of zinc sulfate heptahydrate (.25 g + .03 grams if zinc sulfate is used) into the small test tube. Dissolve the sample in 2 mL of deionized water. Make sure al of the powder is mixed with the water, stopper the test tube and shake for about 1 to 1 ½ minutes to dissolve. Let the test tube stand and weigh another small test tube. Depending on what is being used, .61 g +.03
The purpose for this procedure is for students to familiarize themselves with how different types of properties can lead up to identifying substances. For the safety of this experiment be sure to always have your goggles on and tightly secured, due to any splattering of chemicals or glass breakage. Under no circumstance should any chemical be near your mouth. In this procedure students will use four methods that will help identify what is their unknown substance. Once all methods are done its data will provide physical properties of numerical values which students will compare to the list that will lead to identifying their pure substance. The four methods in this experiment are finding the density (g/mL), the solubility, the melting point
In this lab, solutions were separated by polarity and affinity to solids by chromatography. Chromatography is the separation of a mixture, where the components move at different rates up a medium. The medium used was chromatography paper, matched with a series of developers to aid in movement of compounds upwards. The distance moved up the paper is measured and the rf is calculated. The distance the pigments traveled is divided by the distance developer traveled. The more polar a substance the further it travels up the paper. The paper works by capillary action and absorption to separate the compounds.
There are five factors which affect the rate of a reaction, according to the collision theory of reacting particles: temperature, concentration (of solution), pressure (in gases), surface area (of solid reactants), and catalysts. I have chosen to investigate the effect of concentration on the rate of reaction. This is because it is the most practical way to investigate. Dealing with temperatures is a difficult task, especially when we have to keep constant high temperatures. Secondly, the rate equation and the constant k changes when the temperature of the reaction changes.
In this lab, the law of conservation of matter is involved, which is the law that matter is conserved, it can’t be created or destroyed. This is used in our lab because after separation, the mass of the three substances combined should equal the original mixture. There are also three states of matter that are used in this lab, solid, liquid, and gas. The iron filings and sand are solid, the salt water solution is a liquid, and when the water evaporates, it is a gas. To separate the mixture we were given, we needed to use three different separation methods. These consist of magnetism, filtration, and evaporation. The first is magnetism, which is the force that can attract or repel objects. We used the magnet to