Lab 3 Stoichiometry lab report PDF

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Stoichiometry formal lab report...

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Lab 3- Stoichiometry

Isabella Gilbreth Partner- James Finch College of Science, Engineering, & Technology, Grand Canyon University CHM-113L: General Chemistry Lab F1230A Tamara Avezbadalov November 12, 2021

Abstract Chemical reactions taken place when atoms bonds are formed or separate. Usually when a chemical reaction happens the reactants combine and produce products. This lab report explains how stoichiometry is used in chemistry. Stoichiometry is demonstrate through the reactions between hydrochloric acid with potassium carbonate or sodium carbonate. The results concluded that when an acid and carbonate combine it produces a salt, carbon dioxide, and water. The first reaction between hydrochloric acid and sodium carbonate produces a 115% percent yield meaning it more sample was recovered from the reaction. The reaction between hydrochloric acid and potassium carbonate produced a percent yield of 90.74% meaning it did lose some substance during the reaction. The percent yield over 100% can indicate possible errors of other substances or chemicals were added to taint the pure substance thus the mass was greater than it should have been. A big part in understanding chemical reactions come from prior knowledge of the law of conservation of mass and stoichiometry.

Introduction/Overview Stoichiometry is a subject in chemistry that shows how the law of conservation of mass is used in chemical reactions. When a balanced chemical equation is created, stoichiometry is defined as the relationship of the number of moles between the products and reactants in a chemical reaction. The first rule of thermodynamics is key to remember that matter cannot be created or destroyed (Brown, 2018). This is represented when the chemical reactions that happen between HCI with NaCO3 and also when HCI is mixed with K2CO3. Based on stoichiometry it can be used to determine the number of products produced. Yields also known as reaction yields can be used to predict the ratio of moles between products and reactants (Brown, 2018). Theoretical yield is known as if all the reactants were converted into products perfectly. On the contrary actual yield is the amount of reactants that were actually converted into products in the chemical reaction. The difference between the theoretical and actual yield of a chemical reaction is the percent yield. Percent yield shows if the chemical reaction didn’t pan out perfectly by the loss of some substances in the reaction. Usually, percent yield is lower than the theoretical yield because not every reaction was performed correctly. The results of the lab will demonstrate that the law of conversation of mass is true and stoichiometry in chemical reactions. The main goal is to represent how stoichiometry occurs between the reactions of HCI and NaCO3 and then HCI with K2CO3. A hot plate was used to heat the chemicals and allow for the reactions to take place. When the reactions happened, a new salt was formed as a product. Then the initial mass was compared to the final mass at the end of the experiment. The resulted masses of the experiment were applied to compute the percent yield of the reactions and compare them to the theoretical yield value. Reactions between HCI and NaCO3 or K2CO3 plus the measurements and calculations of percent yield showed how stoichiometry is used in chemistry.

Stoichiometry is relevant in our everyday life because it’s made it possible to have things such as salts, soaps and even helps in cooking. It is important for scientist to use stoichiometry when creating common products for the public. It can help them in calculating precise numbers and comprehending chemical reactions. Scientist can know the accurate number of products produce in a chemical reaction instead of was predicted. Data and Calculations

Results and Discussion The reaction between Na2CO3 and HCl it should also conserve mass. This will lead to the chemical reaction between those will create the following balanced equation: Na2CO3 (s) + 2HCl (aq) -> 2NaCl (s) + H2O (aq) + CO2 (g). The theoretical yield of NaCI was 0.55g, but the actual yield was 0.62g. From those values the percent yield was calculated to be 115%. The

value being over 100% means the mass was increased. This could be due to the errors of miscalculation and or the addition of other substances to the reaction. Between the first reaction of hydrochloric acid and potassium chloride the mass should be the same from beginning to the end due to the law of conservation of mass. Chemical reaction of K2CO3 and HCI here is the balanced equation K2CO3 (s) + 2HCl (aq) -> 2KCl (aq) + H2O (l)+ CO2(g). The chemical reaction theoretical yield is 0.540 grams, but actual yield was 0.490. The percent yield of KCl was 90.74%. This means that the results that weren’t calculated correctly. Errors could have happen due to inaccurate measurements, incorrect calculations, and or the reactions did not occur correctly. Mass was loss from the reaction, and it generated water and carbon dioxide. Even though mass was lost that was due probability to errors, but the law of conversation still stands to be true. The errors could have been using the instrument incorrectly, miscalculations, and or inaccurate measurements. Miscalculations could have occurred when choosing the number of significant figures and during the calculation percent yield. Miscalculations or inaccurate measurements can throw off one’s results entirely. Checking and rechecking data can help minimizes this mistake. Random errors are expected when a small number of trials were done. But can be improve or prevented if more trails can be done. As well as recognizing mistakes then correcting them in the future trials could help. For further trial replications, the margin of error could be improved by doing more trials with consistent measurements, and the same individuals or partners performing all trials. Conclusion The purpose was to represent how stoichiometry occurs between the reactions of HCI and NaCO3 and then HCI with K2CO3. The trials were supposed to demonstrate how the law of

conservation of mass is applied in chemistry. The calculations of theoretical and percent yield for reactions were telling if the reaction converted all its reactions to products. To have a more accurate results in future experiments can be done by conducting more trials, rechecking calculations, measurements, and learning how to use the instruments correctly.

References Brown, T. E., LeMay, H. E., Bursten, B. E., Murphy, C., Woodward, P., & Stoltzfus, M. E. (2018). Chemistry: The central science (14th ed.). Retrieved November 1, 2021, from http://www.gcumedia.com/digital-resources/pearson/2018/chemistry_the-centralscience_ebook_14e.php.

Deo, R. P. (2017). Laboratory manual for general Chemistry I. In Grand Canyon University (Ed.), Laboratory manual for general chemistry I (2nd ed.). Retrieved November 1, 2021, from https://lc.gcumedia.com/chm113l/laboratory-manual-for-general-chemistryi/v2.1/#/chapter/3...