Stoichiometry Lab Report

Objectives In this lab, you will investigate the percent composition by mass of CO2 in Alka-Seltzer® tablets. In addition, you will find out how much CO2 is released into the atmosphere as 2 Alka-Seltzer® tablets chemically react in vinegar. Procedure 250-mL beaker 100-mL graduated cylinder Scale 60 mL of Vinegar 2 Alka-Seltzer® tablets

A buffer solution minimises change in PH of a solution when small amounts of acid or alkali are added to the solution, with an an acidic buffer solutions maintaining a PH<7 (ChemGuide, 2017). It works through an equilibrium, so if the concentration of H+ or OH- are changed, equilibrium will shift to oppose this change and return solution PH to original value. The Alka Seltzer mixture contains an excess amount of the bicarbonate ion which is vital for the buffering action taking place within the solution. This is because the excess bicarbonate ion present, allows the solution to act as a buffer as it’s able to react with small quantities of acids and bases added to the solution, therefore resisting a change in PH by neutralising them.

In our project we mixed different sizes of tablets and water and see if there is a reaction. The tablets are solids and the water is a liquid we are trying to see what happens when they collide. When Alka-Seltzer have many compounds in them. Alka-Seltzer is a medicine that is used to treat heartburn. It is made by many ingredients, which are bicarbonate, aspirin and citric acid.

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.

They use a “Siemens Ultramat three nondispersive infrared gas analyzer with a water vapor freeze trap” to collect levels of carbon dioxide. Can one of these determine the amount of carbon dioxide in alka seltzer tablets? Possibly, but they are not readily available. Another way to test carbon dioxide levels is using the eddy covariance technique.

Introduction Alka-Seltzer has been on the market since 1931 and has helped to relieve indigestion and upset stomach. The tablets began to fizz and bubble when dropped into water. “The fizziness happens when baking soda (sodium bicarbonate) and citric acid react chemically in water. They yield sodium citrate, water and carbon dioxide gas, which causes bubbles.” Based on this information, we will measure the reaction time of AlKa- Seltzer dissolved in 200 ml of water at 3 different tempertures in the first portion of this experiment.

The bottle was labeled “Alka-seltzer” with a sharpie. Container 4: Acid Rain/ Alka-seltzer 650mL of water was added to the container Sulfuric acid was added to the water drop by drop until the solution had a pH of about 4.0 6 alka-seltzer tablet were dissolved into the solution. The bottle was labeled “Alka-seltzer & Acid Rain” with a sharpie.

Alka seltzer started with a pH of 6.5 and barely fluctuated with each new drops added it finished with a pH of 6.47 showing

Determining when exactly the titration was complete was based entirely on the color of the solution. Reaching the titration equilibrium may have been difficult solely from the patience and concentration it took to recognize when to stop adding the base solution. Because the color was observed by every individual running the experiment, there is bound to be variations on the stopping points. In order to help neutralize the solution entirely, carbon dioxide was added to the solution in the form of a breath. It is difficult to measure the amount of carbon dioxide in a breath, and therefore may have led to incorrect calculated

The topic of research is, “how fast does an Alka-Seltzer tablet make gas?”. In the experiment, the scientists will be measuring the chemical reaction rates that occur, when 1 Alka-Seltzer tablet is placed in a specific temperature of water. The independent variable during the experiment will be the temperature of the water (degrees Celsius). The dependent variable during the experiment will be, the rate in which gas is produced (in seconds). The constants of the experiment, will be the amount of water used and the Alka Selter compound.

The excess bicarbonate however, is responsible for the buffering action of the mixture. This therefore helps in stomach upsets and relieves symptoms of heartburn. The advantages of Alka seltzer are that it is easy to ingest as it dissolves fast due to the components

Alka-Seltzer is something that when it gets put into water it has a chemical reaction because it starts to bubble up and when it starts to bubble up the bubbles are carbon dioxide gas. Chemical reactions start when matter is mixed with other matter, you can recognize new compounds by their color or by their acid levels or how a compound looks, feels, or how it acts. Substances create a solid compound. The chemical reaction also happens from more products and properties. They can have one or more products or properties.

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.

If only one reactant is increased, then the chemical reaction will only produce a certain amount of products after the limiting reagent is used up, and in this experiment, the most mass the reaction could produce was 0.4 grams. Although we kept adding calcium chloride, not adding sodium hydroxide in the same proportions will not yield more product, which is the main goal in conducting this lab. We should have seen a plateau at 0.4 grams to show that the limiting reagent inhibited further Ca(OH)2 production, but we made several mistakes in our experiment, which made the data unusable to conclude. Once again, the data is polluted, so these number are not accurate, but it is the data our group has to work with. The theoretical yield should have been more than the actual yield, and the percentages should have been less than 100.

Baking Soda Lab: Roshan Gill Background: In this unit, we began to learn about stoichiometry; where we measure and compare how many chemicals we have, before and after the reaction. Balancing moles and balancing equations are large components in setting up a problem. Another component that we have studied is the yield of reaction (how much product you get). When doing a stoich problem the amount of product you get is a theoretical yield.