I lit the burner fuel, placed it under the burner stand, and placed the aluminum cup containing the alum crystals on the burner stand. I then removed and reapplied the burner fuel under the stand to avoid heating the crystals too quickly and splattering. Once the alum crystals started to boil, I then left the burner fuel under the stand and waited and watched for 8 minutes. I then removed the burner fuel, allowed the alum and aluminum cup to cool, and then weighed the mass and recorded the findings in the data table. I repeated the heating and measuring process 2 more times recording the masses in the data table.
Using a Buchner funnel, a hose, and a suction flask we created a vacuum filtrator which we used to help remove the remaining liquid on the copper so that we may make a more precise measurement of the mass of the remaining copper. Our final mass of copper was .7951 grams. Results and Discussion: Initial Mass of Cu: .25 grams When we mixed the 5 ml of 6 molar HNO3 the copper had disappeared, indicating it had been used in the reaction. The copper had undergone a single replacement reaction and a decomposition reaction. Initial equation: Cu(s) + HNO3(aq) -> Cu(NO3)2(aq) + NO2(g) +H2O(l) Balanced: Cu(s) + 4HNO3(aq) -> Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l) The copper had replaced the Hydrogen in the HNO3 and the NO3 had also broken down into NO2 and O2- allowing the H+ to bond with it and create
Experiments and Data See Attached (Page 86-91 of Lab Manual) Analysis Per the lab manual’s instructions, 1 g of CaCl2 + 2H20 was measured out and added to 25 mL of distilled water; the water had to be distilled to remove the impurities found in merely filtered water, and would therefore skew the results. This formed our first solution, calcium chloride. What we didn’t know going into the experiment was how much of the Na2CO3 would be needed to complete the experiment, so using stoichiometry we determined that the mass of the crystals needed to complete the reaction was around .68 g of Na2CO3. This was mixed with another 25 mL of distilled water, forming our sodium carbonate solution. The two solutions were mixed, forming a precipitate called calcium carbonate.
The tip of the inner blue flame is the hottest portion. 4. How will you know in this experiment when the hydrate BaCl2*2H20 has been completely dehydrated? It will be completely dehydrated when the difference in successive weights of the crucible, cover, and residue (after cooled to room temp.) is 0.0020 g or less.
2: First you measure the mass of the copper tacks and also try to get the mass of the water in the thermos as close to 0.1 kg since 1 dl of H20 = 0.1kg H20. 3: Using the test tube holder, sink the test tube with the copper in it into the 4: The electric kettle is now supposed to make the water boil and raise the temperature of the copper as close to 100ºC (T1cu) but it is not very likely that you will get exact 100ºC due to heat loss. This step will almost certainly take a couple of minutes. 4: Measure the temperature of the water in the thermos (T1w) and then add the tacks to the water in the thermos. 5: Now measure the temperature of the water (T2cu and T2w will have the same temperature).
Turn on the hot plate to a medium heat. Wait until all the liquid has evaporated from the substance and then record the color of the dried substance. 6) Repeat steps 1-5 using each of the three other substances. NOTE: Make sure to wipe down all the materials before they are reused. Compounds | Solubility in Water | Solubility in Alcohol | Color if Soluble in H₂O | Conductivity(Scale 1-4) | Color When Dry | Melting Point (°F) | Sucrose | Yes | No | Transparent | Medium (2) | Brown | 366.8 | Sodium Chloride | Yes | No | Transparent | High (3) | Crystallized, Clear | 1474 | Sodium Carbonate | Yes | No | Mostly Transparent | High (3) | White | 1564 | Salicylic Acid | No | Yes | N/A | High (3) | White | 318.2
Add the HCl SLOWLY to the magnesium by running it down the side of the beaker. Adding the acid too quickly will result in the spattering of the acid. Write down any observations of the reaction. 6. After all the acid has been completely added and the reaction has stopped, use a pipette to add a few extra drops of acid into the beaker until the reaction stops.
The watch glass was removed with the beaker tongs. Using a rubber bulb and a stirring rod to stir the solution continuously, 15.00mL of .25M BaCl2 solution was added to the solution in the beaker. The watch glass is replaced and the solution is keep hot but not boiling for 15 minutes. The precipitate was allowed to settle. When the liquid above the precipitate was clear, the solution was tested for completeness of precipitation when a few drops of BaCl2 solution were added from a pipette.
Every few minutes, the lid of the crucible was lifted carefully with a tong to see if the magnesium had started to burn and also to left some air enter the crucible to make the experiment more efficient. 6. When the magnesium had completely reacted, the crucible was heated strongly without the lid on for few minutes. Then, the crucible was placed on gauze for it to cool down. 7.
After 10 seconds, the colorless mixture suddenly turns blue. Concept: Demonstrates a typical clock reaction; shows the effect of the interaction between chemical reactions that have different rates. Materials: • Solution A o 0.6 grams Starch o 30 mLs of Acetic Acid o 4.1 grams of Sodium Acetate o 50 grams of Potassium Iodide o 4.7 grams of Sodium Thiosulfate ▪ Allow mixture to cool and dilute to 1 liter with distilled water o 1 liter flask • Solution B o 500 mLs of 3% Hydrogen Peroxide o 500 mLs of distilled water o 1 liter flask o Safety: Hydrogen Peroxide can be irritating to skin and eyes. Wear safety goggles and gloves. Procedure: Mix the two solutions together.