Finding the Ratio of Moles of Reactants in a Chemical Reaction I. Purpose The purpose of the lab is to be able to find the ratio of mole reactants in the chemical reaction. The lab uses the method of continuous variations in order to determine the mole ration of two reactants. The chemicals that were used in the lab where sodium hypochlorite (NaClO), and sodium thiosulfate (Na2S2O3). II.
Now to begin, pour 50 mL of the sodium phosphate buffer solution with a pH of 6.84 into the 150 mL beaker. From here on out, the sodium phosphate buffer solution will be referred to as simply the buffer solution. Next, locate the indicator called bromothymol blue (0.04%) and add 20 drops to your 150 mL beaker. The solution should then appear green. Next, obtain a 5 mL serological pipet and thoroughly rinse it with the buffer solution, then discard the buffer solution into the 250 mL beaker.
Introduction: Stoichiometry is the branch of chemistry concerned with measuring the proportions of elements that combine during chemical reactions (Bing). The mole ratio, which is the comparison of moles of a given reactant or product in an equation, is essential to the proper usage of stoichiometry. In the following experiments, stoichiometry and mole ratios were used to accurately predict and obtain missing proportions from the given equations. In the stoichiometry of a neutralization reaction experiment, the molarity and type of acid were predicted by the titration of an unknown acid using .1 molar (M) Sodium Hydroxide (NaOH). In the other, aluminum leftovers, the activity series was used to understand how and why the reaction took place and stoichiometry was used to predict the amount of aluminum that should have reacted in the following equation: 3CuCl2 * 2H2O (aq) + 2Al (s) 2AlCl3 (aq) + 3Cu (s) + 6H2O Stoichiometry’s importance in the laboratory is well defined in the results of the previously mentioned experiments.
Lab Assignment #8 Name: Jose Manuel Hernandez Jr. Report Submitted: 04/10/15 Title: Stoichiometry of a Precipitation Reaction Purpose: The purpose of this experiment is to learn about precipitation reactions and their characteristics. Also, you will learn about the molarity and molar mass of a substance and how they can be used to calculate one another. Another thing is that you will learn how to calculate what the theoretical maximum amount of product is and see the difference in your theoretical and actual amount is and what percent yield it gives you. Procedure: 1. Measure 25 mL of water into a graduated cylinder.
BACKGROUND: For these experiments a 96-well plate was used. Each chemical listed would be put into their own well of 2 drops of each chemical unless instructed otherwise. After the chemicals were each dropped into the wells they were stirred with a different toothpick each time (to not cause cross contamination) and then was observed over a white piece of paper and then a black piece of paper. For each reaction I recorded the well number and took detailed notes on the reactions observed. After the first two tests done with BTB I hypothesized that acids would turn BTB yellow and that bases would remain blue.
Objectives: The purpose of this lab is to observe the reaction of crystal violet and sodium hydroxide by looking at the relationship between concentration and time elapsed of the crystal violet. CV+ + OH- CVOH To quantitatively observe this reaction of crystal violet, the rate law is used. The rate law tells us that the rate is equal to a rate constant (k) multiplied by the concentration of crystal violet to the power of its reaction order ([CV+]p) and the concentration of hydroxide to the power of its reaction order ([OH-]q). Rate = k[CV+]p[OH-]q To fully understand the rate law, concentrations of the substances must be looked at first. The concentration is measured in molarity.
EXTRACTION: DETERMINATION OF ITS EFFICIENCY AND CALCULATION OF THE DISTRIBUTION COEFFICIENT Group#4: Wassim Abdel Naby and Bianca Francisco Bachelor of Science degree in Chemistry De La Salle University ABSTRACT The objective of this experiment is to demonstrate the concepts of extraction and to calculate the distribution coefficient. In the process of extraction, amount of acetic acid was the one to be determined, and this was done through the process of titration, indicator used was phenolphthalein and the titrant used was Sodium hydroxide. First, 20 ml aliquot portion of diluted acetic acid in a 125 mL Erlenmeyer flask titrated with Sodium hydroxide. Next, the second flask containing another 20 mL of acetic acid extracted by 20 mL portion toluene, this was done twice due to over titration in the first trial. Lastly, the third 20 mL aliquot portion acetic acid underwent the same procedures with flask 2 but this time with two 10 mL portions of toluene.
Each of these types of reactions behaves in a similar fashion. They all involve the conversion of one substance to another substance, while preserving the original elements in some form. Another aspect of predicting products is the chart of reactivity. In order for the replacement of an element in a compound to happen, the element replacing the original element must be more reactive. The chart of reactivity tells chemists the comparable reactivity of elements.
In station B we tested the chemical reaction of decomposition; decomposition is the chemical reaction where the chemical compound is separated into elements or simpler compounds. In station C we tested the chemical reaction of double displacement; double displacement is the reaction where two compounds are replaced by two other compounds. In station D we tested the chemical reaction of single displacement; single displacement is when one compound is replaced by another compound. Each station is testing the law of conservation of mass by using each method in the lab. Purpose The purpose for this lab is to study the law of conservation of mass by using synthesis, decomposition, single replacement, and double replacement.
Calculations involving the Mole, Avogadro’s Number, Molar Mass, Mole-Mole and Mass-Mole calculations in chemical equations. Combustion analysis and calculation of empirical and molecular formulas from composition analysis. Electrolytes and non-electrolytes. Precipitation reactions and solubility rules. Writing balanced molecular equations and net ionic equations.