ADI Lab: Stoichiometry and Chemical Reactions The guiding question of this ADI lab was, “Which balanced equation best represents the thermal decomposition of sodium bicarbonate?” The goal of this lab was to use our knowledge of stoichiometry with the mole ratio to identify the correct chemical equation for the decomposition of sodium bicarbonate. Information that was given going into this investigation was the definition of the law of conservation of mass and the atomic theory which states that no atoms can be created nor destroyed during a chemical reaction. Also the mole ratio which is used to determine how much of a product will be produced in a chemical reaction using the given chemical equation. To conduct the lab, information regarding …show more content…
Before decomposing the sodium bicarbonate, the crucible mass was measured as well as the mass of the crucible with two grams of sodium bicarbonate in it. Two grams of sodium bicarbonate was used because it seemed like a reasonable amount for the size of the crucible and is an easy number to work with in stoichiometry. The sodium bicarbonate was cooked in the crucible for 14 minutes and then the gas was turned off and the crucible was left to cool for 5-10 minutes. Since no information on how long to cook the sodium bicarbonate was given we used our best estimate of how long the substance needed to decompose based off how much was placed in the crucible. Once the crucible was cooled, it was placed on a balance to measure the mass and then subtracted by the mass of the crucible to get the solid product’s mass. Then dimensional analysis was used to find the theoretical yield for the solid substance of each given equation. Starting with 2.0 gram of sodium bicarbonate, the molar ratio from each equation was used to convert from moles of sodium bicarbonate to moles of the solid product in that equation and then molar mass was used to convert the answer back into grams. Once this step was repeated with all four equations the theoretical yield of each was compared with the actual yield found by decomposing the
In order to begin this experiment, first one must find the balanced chemical equation for the reaction which occurs between the aluminum and copper (II) chloride. This balanced equation being 2Al(s)+3CuCl2 (aq)3Cu(s)+2AlCl3 (aq). After finding this equation, one must use the process of stoichiometry in order to find how many grams of aluminum are needed in order to produce 0.15 grams of copper. In this experiment, the purpose was to produce between 0.1 and 0.2 grams of copper, so one should attempt to produce 0.15 grams of copper seeing as it is the average of those two numbers. The first step in the stoichiometric process which one has to complete is finding how many grams of copper are in one mole of copper.
Procedures In this experiment, an unknown mixture was given, that contained both sodium bicarbonate(NaHCO3) and sodium chloride(NaCl). The purpose of this experiment was to find the percent (%) composition of the sodium bicarbonate and sodium chloride in the unknown mixture. Hydrochloric acid(HCl) and a scale were materials that were also used during the lab.
In order to find the amount of a product made during a double displacement reaction, the product has to be separated from the solution. From this number of moles of precipitate can be calculated. From there the number of moles of reactants can be calculated using the mole ratios of the particular reaction that occurred. As seen in Table 5 it is shown that by finding out the number of moles of the unknown, the molar mass of the unknown can be calculated. From the found mass of the unknown compound, the mound of the original ion can be found.
Cassie Droelle 1510-01501 Chemical Equation 2 Visualizing Stoichiometry – Inquiry Lab Cassie Droelle 1510-01501 4-18-16 Introduction The purpose of this lab is to determine the complete balanced equation of a metathesis reaction with an unknown metal ion by first experimentally identifying the metal ion and then using stoichiometry to determine the rest of the equation. Stoichiometry is “the process by which quantities in a chemical reaction are compared” and is based on the Law of Conservation of Mass (1). The Law of Conservation of Matter “dictates that the mass of the reactants and mass of the products must be equal” (1).
For this lab the knowledge to tell the difference between a chemical and physical changes was needed. To tell this the knowledge of the five signs of a chemical change was needed. These five signs are color change, odor change, production of bubbles/gas, production of heat/light, and the production of precipitate. Also prior to the lab one question was provided that needed to be answered. This question was what chemical must be present for a color change.
The topic of this lab experiment is the relationship between percent yields and limiting reagents, and how it relates to copper (II) sulfate and aluminum foil. The objective was to determine the limiting reagent in a reaction and calculate the percent yield. To understand this, fundamental concepts of percent yields and limiting reagents are essential. A percent yield is defined as the ratio of the actual yield, to the theoretical yield in a reaction, expressed as a percent (Haberer, Salciccioli, & Sanader, 2011). This is useful as several impurities in this reaction possibly contributed to the percent yield.
So if 0.38 is divided by 0.49 and multiplied by 100 then the percent yield for Zinc Sulfide would be 77.6%. When it comes to Sodium Chloride, the theoretical yield is 0.58 grams and the actual yield is 0.45 grams. So when 0.45 grams is divided by 0.58 grams and multiplied by 100, the percent yield would be 77.5% of Sodium chloride. The actual yield is directly taken from the mass of the products in the experiment while the theoretical yield is determined by using stoichiometric calculations. To determine the theoretical yield, the reactants should be converted from grams to moles based on the coefficients in the chemical equation and the moles should be incorporated into the mass of the reactants.
The purpose and significance of this experiment was to find the specific heat and figure out an identification of an unknown metal. The specific heat was calculated through a given formula. The unknown metal was found through descriptions that matched the unknown metal. The unknown elements would be one of the following: Al, Bi, Cd, Cu, Fe, Pb, Ni, Na, Sn, or Zn. First the specific heat of water was measured, then heat flow was measured using equations.
According to Modern Chemistry, stoichiometry is “the mass relationships between reactants
I. Title: Mass and Mole Relationships in a Chemical Reaction II. Background: Percent yield is the ratio of actual yield to theoretical yield. Amount in percent of one product formed in chemical reaction. Actual yield is the information found is experiments or is given.
The actual yield of the reaction was 4.411 grams of copper and was obtained through the experiment
The reaction mixture: R_F=2.9/4.5 = 0.64 The final product: R_F=1.9/4.5 = 0.42 Table of calculations Benzaldehyde Acetone Sodium Hydroxide Ethanol Dibenzalacetone Co-efficient 2 1 1 1 1 Volume (ml) 4.04 1.5 30 Grams used (g) 4.2 1.185 4 0.95 2 Formula weight (g/mol) 106.12 58.08 40 46.07 234.29 Moles 0.0396 0.02 0.1 0.02 Moles/ Coefficient 0.02 0.02 0.1 0.02 Density 1.04 0.79 (1) Calculations Mass Impure compound mass: 2.02g Final compound mass: 2.88g Dibenzalactone = (4.2×234.29×1)/(106.12×2) = 4.64g (theoretical
Stoichiometry is a method used in chemistry that involves using relationships between reactants and products in a chemical reaction, to determine a desired quantitative data. The purpose of the lab was to devise a method to determine the percent composition of NaHCO3 in an unknown mixture of compounds NaHCO3 and Na2CO. Heating the mixture of these two compounds will cause a decomposition reaction. Solid NaHCO3 chemically decomposes into gaseous carbon dioxide and water, via the following reaction: 2NaHCO3(s) Na2CO3(s) + H2O(g) + CO2(g). The decomposition reaction was performed in a crucible and heated with a Bunsen burner.
However, the process is both time and temperature dependent, with conversion 90% complete within 75 minutes at 93°C. The reaction proceeds via surface-controlled kinetics; when sodium bicarbonate crystals are heated for a short period of time, very fine needle-shaped crystals of anhydrous sodium carbonate are formed on the sodium bicarbonate surface. Sodium bicarbonate is stable in dry air but slowly decomposes in moist air and should therefore be stored in a well-closed container in a cool, dry place. 5.9. TALC83:
(0.01 moles of NaOH) x (1 mole Ca(OH)2/ 2 moles of NaOH) = 0.005 moles of Ca(OH)2 Tube 1: (0.0020 moles of CaCl2) x (1 mole Ca(OH)2/ 1 mole of CaCl2) = 0.002 moles of Ca(OH)2 (0.002 moles of Ca(OH)2) x (74.08 grams/mole) = 0.1 grams = theoretical yield Tube 2: (0.0035 moles of CaCl2) x (1 mole Ca(OH)2/ 1 mole of CaCl2) = 0.004 moles of Ca(OH)2 (0.004 moles of Ca(OH)2) x (74.08 grams/mole) = 0.3 grams= theoretical yield Tube 3 (0.0050 moles of CaCl2) x (1 mole Ca(OH)2/ 1 mole of CaCl2) = 0.005 moles of Ca(OH)2 (0.005 moles of Ca(OH)2) x (74.08 grams/mole) = 0.4 grams =theoretical yield Tube