Q=mc∆T m∆H=-(q) Obtain a vial containing an unknown chloride salt. Disclaimer: This work has been submitted by a university student. Our unknown salt was another source of material given by our teacher, and this allowed us to complete the experiment. These errors were recorded and explained to better help us prevent it from occurring again. Q=mc∆T If you need assistance with writing your essay, our professional essay writing service is here to help! 2014. Other materials needed in order to complete the lab included paper towels. Lastly, we measured the 3.0grams of our unknown salt and placed that into the water, letting it dissolve, and measured the temperature. By following the correct procedure and having the correct materials required, we were able to determine the final enthalpy. Web. Print. The result of this error had a medium effect on our data and due to this effect, our enthalpy wasn’t as accurate, and didn’t exactly match the ones in the textbook. In accordance, not only will we have been given the incorrect enthalpy, but the results were affected as well. 2014. This source of error had a large effect on our solution because we had no way of determining whether it dissolved or not, without tampering the solution. Confirm that the gas is ammonia - damp red, Dilute nitric acid and silver nitrate solution added, Dilute hydrochloric acid and barium chloride solution added, Dilute sodium hydroxide added, then warmed, Smelly gas produced that turns damp red litmus paper blue, Salt A is sodium chloride, NaCl. The cylinder was to give us the accurate measurement of whether we had exactly 25ml of water or not. Throughout the cold pack experiment not all our results were accurate. Looking for a flexible role? Be sure to note the identification letter or number of your unknown. These errors were recorded and explained to better help us prevent it from occurring again. The theories that needed to be taken into account for to help complete the lab, includes determine the heat capacity, q=mc∆T. There are a number of ways that you could identify the ions in unknown salt in Chemistry. Q= -0.7315KJ ∆H=0.2438KJ/g Repeat any tests that do not get clear results. The yellow flame colour shows that Na+ ions are present, and the white silver halide precipitate shows that Cl- ions are present. From this chart above, we can see that we completed three trails to determine the exact value of the unknown salt, and to determine what the unknown salt is. dip a clean wire loop into a solid sample of the compound being tested, put the loop into the edge of the blue flame from a Bunsen burner, observe and record the flame colour produced, Add a few drops of dilute sodium hydroxide solution. I would hold the middle of the calorimeter and spin it around to better dissolve the unknown salt. You may need to dissolve a sample of salt in a little distilled water if you are given solids, rather than solutions. After determining the value of that, we divide it by the theoretical value and multiply it all by 100%. The equation used to determine change in temperature and percentage yield are, ∆T= T1 – T2 and. All work is written to order. Observe and record the colour of any, Add a few drops of dilute sodium hydroxide solution, then warm gently. The equation above allows us to determine the q, which is the quantity of heat transferred, which equals the mass (m), multiplied by the specific heat capacity (c), and multiplied by the change in temperature (∆T=T2 – T1 ). “DoChem 095 Heat of Solution of Magnesium.”DoChem 095 Heat of Solution of Magnesium. As we already know that the reaction was endothermic and since it’s endothermic the solution absorbed the heat, from the cups and reaction. The equation above allows us to solve for the ∆H system. WhatsApp. 1. N.P., n.d. A 100ml graduated cylinder was used to determine the accurate quantity of water required. The equation above gives us the average enthalpy for the number of trails that was conducted by our group. After calculating for our enthalpy, we can take the theoretical yield, found on page 347, table 1 in our textbook, we can subtract is by the actual yield. Flame tests and chemical tests are used to detect and identify ions in samples. C; MORTENSEN, B; BJØRNLAND, T; OLSEN, I. Chemistry This can then be tested in other organic solvents like ethyl alcohol, acetone, benzene, etc. This makes it difficult to tell whether a precipitate is really white, or just cream or yellow that is too pale to be sure. Identifying a Simple Salt. Characteristic smell helps to identify some anions such as acetate, sulphide etc. Therefore, this points to the compound being ionic. The cold pack experiment lab allowed us, the students, to apply theories learned in class to actual real life experiments; such experiments prepare us for future tasks the will be put forth to determine. This is an outline of the required steps to undertake one of these methods. Toronto: Thomson Nelson, 2003. N.p., n.d. Qualitative analysis: test for ions. We determined the heat capacity using the equation q=mc∆T and the enthalpy using m∆H=q. “DoChem 095 Heat of Solution of Magnesium.”DoChem 095 Heat of Solution of Magnesium. Instrumental methods of analysis are faster, more accurate and more sensitive than simple chemical tests. 2014. It hadn’t affected our results by a large quantity because the difference between the solution we were supposed to get and the one we had, had a small margin of differences. Brain, Marshall , and Sara Elliot. “DoChem 095 Heat of Solution of Magnesium.”DoChem 095 Heat of Solution of Magnesium. The first method used will be the Fajan titrimetric method which uses an adsorption indicator. N.p., n.d. Toronto: Thomson Nelson, 2003. 174-76. 13oC N.p., n.d. From that point we calculated the change in the temperature for each trail, with the equation, ∆H=T2 – T1.