Sammi Manis
September 28, 2015
Experiment #04
Determining the Mole Ratios in a Chemical Reaction
CHEM 1315- 012
Purpose:
In this experiment, the experimenter will use two common substances to help determine the mole ratios in the reaction. The two substances are a hypochlorite ion from bleach and a thiosulfate ion used in a solution to develop film.
Using continuous variations, the experimenter will prepare different mixtures using the two reactants that will have the same total volume and total number of moles of reactants. Since the reaction will be exothermic, the mixture with the most heat energy will be the one that fully reacts both the hypochlorite and the thiosulfate ions, determining the enthalpy change. This
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mixture will be used to find the coefficients, which provides the mole ratio of the reaction. The experiment overall helps determine the unknown product coefficients in an oxidation-reduction reaction. An exothermic reaction is a reaction where the chemicals release light or heat energy.
For example, fireworks are considered an exothermic reaction because they give off energy in the form of heat and light. An endothermic reaction is where the chemicals absorb the light or heat energy from its surroundings. For example, when photosynthesis occurs the plant takes in the light energy from the sun along with carbon dioxide and water to produce sugar and oxygen. The heat taken in would be considered an endothermic reaction.
The limiting reagent (reactant) in a reaction is the substance the controls when a reaction is fully complete. The limiting reactant is fully consumed in the reaction and prevents the reaction from continuing any further. The leftover reactant, or excess reactant, is what is left when the limiting reactant is fully
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consumed. Materials: LabQuest Temperature Probe Two 10 mL graduated cylinders Two 25 mL graduated cylinders Two 50 mL graduated cylinders Styrofoam Cups Two 250 mL beakers One 600 mL beakers 0.50 M sodium hypochlorite, NaOCl, solution 0.50 M sodium thiosulfate, Na2S2O3, solution in 0.2 M sodium hydroxide, NaOH Experimental Procedure: The experimenter must obtain and wear goggles for the entire experiment. To track the materials that will be disposed of at the end of the experiment, use the Chemicals Utilized table on the experiment handout. To begin the experiment, connect the Temperature Probe to the LabQuest and prepare the LabQuest accordingly.
Obtain 200 mL of the sodium thiosulfate solution in a 250 mL beaker, 400 mL of the bleach solution in a 600 mL beaker, and prepare the solutions for the experiment. Using a graduated cylinder, measure 25 mL of the bleach into the beaker very precisely and pour it into a small Styrofoam cup. To help stabilize the cup, rest it inside of a beaker. Next, measure out 25 mL of the thiosulfate solution in a different or clean graduated cylinder.
To prepare the setup for the experiment, put the temperature probe through the hole in a large Styrofoam cup. Fully submerge the end of the Temperature Probe into the Styrofoam cup of the bleach solution. Slide the Styrofoam cup over the top of the smaller Styrofoam cup to cover the small cup. Do not remove the Temperature Probe from the liquid.
Being the data collection by pressing the arrow in the bottom left corner of LabQuest and let it gather some initial temperature readings. Next, lift of the large Styrofoam cup without removing the probe from the liquid. To mix the reactants, swirl the solution cup gently while making sure the probe remains in the solution the whole
time. The collection will stop after three minutes, but the experimenter may stop the collection before that if the temperature of the solution is no longer changing. Using the X and Y icon on the LabQuest, examine the data gathered and calculate the maximum temperature change of the solution. Record the temperature on the data table. Clean the cup and dispose of the mixture in the aqueous waste container provided, then dry the cup to reuse. Repeat the previous steps for the remaining trials testing various ratios of the two solutions using the correct volumes given in the data table. Keep the total volume of the solution at 50 mL. Start a new date collection by selecting the graph icon, and then the file icon. Finally, properly dispose of all chemical waste and clean any materials used in the experiment.
First, 100 mL of regular deionized water was measured using a 100 mL graduated cylinder. This water was then poured into the styrofoam cup that will be used to gather the hot water later. The water level was then marked using a pen on the inside of the cup. The water was then dumped out, and the cup was dried. Next, 100 mL of regular deionized water was measured using a 100 mL graduated cylinder, and the fish tank thermometer was placed in the water. Once the temperature was stabilizing in the graduated cylinder, the marked styrofoam cup was filled to the mark with hot water. Quickly, the temperature of the regular water was recorded immediately before it was poured into the styrofoam cup. The regular/hot water was mixed for a couple seconds, and the fish tank thermometer was then submerged into the water. After approximately 30 seconds, the temperature of the mixture leveled out, and was recorded. This was repeated three
Start with the hot water and first measure the temperature. Record it. 8. Then pour 40 ml into the beaker. You can measure how much water was used by looking at the meniscus.
The purpose of this experiment was to examine how the stoichiometry, “the quantitative relationships between substances involved in a chemical reaction”, can be applied to determine the quantity of sodium hypochlorite found in a bleach product. This experiment allowed it to determine how much oxidizing agent is in a cleaner by using a redox reaction, which is a reaction involving the transfer of electrons from the compound being oxidized to the compound being reduced. To determine the amount of oxidizing agent, it is necessary to accurately measure out known amounts of redox reactants, know the stoichiometry
The limiting reactant of a chemical reaction is the substance that places an upper bound on the amount of product that the reaction can produce. The limiting reactant places this upper bound because the reaction must stop once all of the limiting reactant is consumed.
5.) One at a time, place your test tubes in the water bath and heat the first test tube to 25 , the second to 50 , the third to 75, and the last to 100 degrees c. Remeber to stir with your stirring rod every so often.
The procedure of the lab on day one was to get a ring stand and clamp, then put the substance in the test tube. Then put the test tube in the clamp and then get a Bunsen burner. After that put the Bunsen burner underneath the test tube to heat it. The procedure of the lab for day two was almost exactly the same, except the substances that were used were different. The
8. Put the closed flask into a water bath at room temperature in a 1 L beaker. Ensure that the entire flask is covered. If the flask begins to float, clamp it down. Put the temperature probe in the water bath. Using a pipet, add some boiling water from the hot plate to the water bath until the temperature of the water bath increases by 3 °C. Use the temperature probe to stir the water bath. Once pressure and temperature measurements stop changing, keep the data. Record the air pressure and vapor pressure for this temperature.
During this reaction the solution gained heat. This is what we were monitoring. The reason why the solution gained heat is because the reaction lost heat. Energy is lost when two elements or compounds mix. The energy lost/ gain was heat. Heat is a form of energy as stated above in the previous paragraph. The sign of enthalpy for three out of the four reactions matches what was observed in the lab. For the last reaction, part four, the reaction gained heat not the solution like parts one through three. The negative enthalpy value for part four indicates that the reaction gained
Planning Firstly here is a list of equipment I used. Boiling tubes Weighing scales Knife Paper towels 100% solution 0% solution (distilled water) measuring beakers potato chips Cork borer. We planned to start our experiment by doing some preliminary work. We planned to set up our experiment in the following way.
Use glassware as directed by your instructor. Place a test tube placed inside a beaker with ice water to collect the product from the apparatus. Obtain the 10mL round bottom flask from the apparatus. Obtain two graduated cylinders of 10mL. On one graduated cylinder measure 4mL (85% H3PO4) of Phosphoric Acid and pour into the 10mL round bottom flask. On the other graduated cylinder measure 3mL of Cyclohexanol and pour into the flask as well. With a pipet add 5 drops of Sulfuric Acid (H2SO4) into the flask. Attach the round bottom flask to the distillation apparatus. Place thermometer with rubber stopper on the apparatus to obtain the temperature Start with the water flow through the condenser. Turn on and heat the reaction until the product starts to distill. Distill and collect until thermometer temperature rises to 85˚C. Once there is no more product to collect obtain the test tube of product. Two layers should be formed, top layer of cyclohexane and bottom layer with water. Obtain a pipette and remove the bottom layer (water) if any. Add 10% (5mL) of Sodium Bicarbonate (NaHCO3) to nuclearize any acid in the solution. Mix well and remove once again the bottom layer of water with pipette. Add 5mL of water and mix well to wash the top layer. After the two layers form again, remove entirely the bottom layer of water and add a few pellets of Calcium Chloride. Obtain a 50mL or 100mL beaker and weigh.
A hot plate is acquired and plugged in and if left to warm up. Fill two beakers with 0.075kg of water and record the temperature using a thermometer and record it. Place one of the beakers onto the hot plate and drop one of the metal objects in. Wait for the water to boil and wait two minutes. Take the object out of the water and drop it into the other beaker. Take the temperature of the beaker and record the rise in temperature.
2. In the large beaker, put water and boil it completely. After that, remove the beaker from heat. 3. Sample tubes (A-D) should be labeled and capped tightly.
In a 250ml beaker place 100mls of water, measure the temperature of the water and record this initial temperature onto a table. Set the timer and add one teaspoon of Ammonium Nitrate to the water, stir this continuously until the Ammonium Nitrate has dissolved. After 1 minute measure the temperature and record it, do this for a further 2 minutes (3 minutes in total). Repeat this process for a total of 10 teaspoons.
Chemical kinetics is the study and examination of chemical reactions regarding re-arrangement of atoms, reaction rates, effect of various variables, and more. Chemical reaction rates, are the rates of change in amounts or concentrations of either products or reactants. Concentration of solutions, surface area, catalysts, temperature and the nature of reactants are all factors that can influence a rate of reaction. Increasing the concentration of a solution allows the rate of reaction to increase because highly concentrated solutions have more molecules and as a result the molecules collide faster. Surface area also affects a
In this experiment three different equations were used and they are the Stoichiometry of Titration Reaction, Converting mL to L, and Calculating the Molarity of NaOH and HCl (Lab Guide pg. 142 and 143).