To Investigate the Rate of Reaction Between Calcium Carbonate and Hydrochloric Acid

Data Tables and Observation: Fill out the data sheet (below) for the experiment and submit with this form. Recording data carefully

In Experiment B the limiting reactant was determined to be CaCl2 when two drops of the test reagent 0.5 M CaCl2 was added to the supernatant liquid in test tube 1, and a precipitate formed. Since there was a reaction, there was C2O42- in excess and Ca2+ is the limiting reactant in the original salt mixture present in test tube 1 . This was further confirmed when two drops of the test reagent .05M K2C2O4 was added to the supernatant liquid in test tube 2. There was no precipitate because Ca2+ was not present since it was the limiting reactant and instead C2O42- was in excess.

= = == Calcium Carbonate + Hydrochloric Acid Calcium Chloride + Water + Carbon Dioxide Equipment ---------

The reaction you will be investigating is the reaction that occurs when an Alka-Seltzer tablet is placed into a given amount of water. Alka-Seltzer is an over-the-counter antacid and pain relief medication that is dissolved in water before it is ingested. Each tablet contains aspirin (acetylsalicylic acid), citric acid, and sodium bicarbonate. As the tablet dissolves in water, the bicarbonate ions in the tablet react with the hydrogen ions from the acids that are also contained in the tablet. The carbon dioxide gas produced by the reaction is what causes the bubbling that can be observed.

Write a balanced chemical equation for the reaction of carbon dioxide with limewater. The formula for the active substance in limewater is on the pipet, and the products of the reaction are calcium carbonate and water.

Present all relevant data in a data table below. Include an observations section for any observations you made during the lab. Make sure you note the data needs to be converted before graphing.

Measure 500ml of tap water in the 500cm3 beaker, then measure 5g of sodium hydrogen carbonate using the 50cm3 beaker and weight scale and place in the beaker of water, using the glass rod to dissolve it into the mixture.

For my procedure, I will put the filter paper in each of the chambers. Then, I will use the dropper to put a small amount of acid on one of the pieces of filter paper, and will do the same with water on the other side. Then, I will place 5 pillbugs on each side of the choice chambers, and I will set the timer to 10 minutes and record how many bugs are on each side every 30 seconds.

10.) Use a clean spatula to place a small amount of the sample from the crime scene into wells J,K and L. Record any physical properties of the sample that you observe.

Most of the physical properties of the unknown substance were typical of Calcium Chloride. The unknown substance was crystals and odorless, just like Calcium Chloride1. However, the unknown substance had a pH of 5 while Calcium Chloride has a pH of 92. This difference could be contributed to other substances in the solution. The solution was made with tap

The volume of carbon dioxide gas produced from a reaction was measured in order to determine what carbonate sample was used. A gas assembly apparatus was used to capture the gas from a reaction between an unknown carbonate and 6M hydrochloric acid; three trials were performed. The mass of the unknown carbonate was determined, and the reaction occurred in a test tube. The volume of gas produced by the reaction was measured, and the partial pressure of carbon dioxide was calculated after the partial pressure of water vapor was determined using Dalton’s Law of Partial Pressures. The percent mass of carbon dioxide gas was then calculated, and the average mass percent was compared to the table of known carbonates. It was concluded that the unknown carbonate sample used in the reaction was magnesium carbonate.

Chemical kinetics is the study and discussion of chemical reactions with respect to reaction rates, effect of various variables, re-arrangement of atoms, and many other aspects of chemistry (http://www.science.uwaterloo.ca/~cchieh/cact/c123/chmkntcs.html). The rate of a reaction can be measured by the rate at which a reactant is used up, or the rate at which a product is formed(http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/chemical_reactions/ratesrev1.shtml). Time it takes for a reaction to occur is affected by temperature, which works with the

= == CaCO3(s) + 2HCC(l) CaCl2 (aq) + H2O(l) + CO2

Collect to 2 large beakers both large beakers are to be filled with hot water (labtutor). Then obtain seven conical tubes these will be used to collect the levels of gas, you will also need test tube a stopper and a plastic tube (labtutor). You want to fill the conical tube to at least 50 ml of water (Cressy). Take the four conical tubes filled with water and place two in each beaker, to do this you must invert the tube and cover the release hole as to not lose any water (Cressy). Then place the beakers with the tubes in the bath so they can be at the same temperature as the bath (Cressy). Next mark all of your test tubes in number order to be sure which tube contains what concentrations and pH (Cressy). Having mixed a solution to the specifications of 2.5 ml of glucose in all tubes, 3 ml of yeast in 2 tubes of pH 5, 2 tubes of pH 9, and the single pH 7 tube, the remaining two tubes will contain no yeast as they will be negative controls. Next add 2 ml of pH buffer 3 tubes will receive pH of 5, three will receive a pH of 9 and a single tube of pH 7. Finally add pure water to make sure all test tubes have 10 ml of solution. When making the solutions

6. The precipitate may have not dried up properly making it so there was water adding weight on it.