Calorimetry Lab

Calorimetry is the science of measuring the change in heat absorbed or released during a chemical reaction. The change in heat can tell us if the reaction is either exothermic - it released or heat into surroundings, or endothermic - it absorbed heat from surroundings. The device used to measure calorimetry is a calorimeter. A calorimeter can range from very expensive lab ones to coffee styrofoam cups but they are all tightly sealed in order to prevent heat from escaping.

The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.

The mole is a convenient unit for analyzing chemical reactions. Avogadro’s number is equal to the mole. The mass of a mole of any compound or element is the mass in grams that corresponds to the molecular formula, also known as the atomic mass. In this experiment, you will observe the reaction of iron nails with a solution of copper (II) chloride and determine the number of moles involved in the reaction. You will determine the number of moles of copper produced in the reaction of iron and copper (II) chloride, determine the number of moles of iron used up in the reaction of iron and copper (II) chloride, determine the ratio of moles of iron to moles of copper, and determine the number of atoms and formula units involved in

Found on Celebrity Airlines Flight 82181 were a number of substances brought on by passengers. Given that the crash was ruled a terrorist attack, identification of all substances found on and in the bodies and luggages of the victims needed to be made. To do this, empirical and molecular formulas were put into use when determining substance identities. Each substance was tested to find the percent composition of carbon, hydrogen, nitrogen, and oxygen, and then used to find the empirical formula of the substance by using 100 grams of each substance to represent 100% made up by the elements combined. The mass of each element in the substance calculated from the percent was then divided by the molar mass of that

Using elemental analysis to determine the percent mass composition of each element in a compound is the first step in creating an empirical formula. There are many different types of elemental analysis, but in this experiment gravitational analysis and Beer’s Law are used. Elemental analysis is first used to find the moles of each element, then converted to mass, and then the percent mass of the element in the product is found (2).

Weight the mass for the different percent of zinc and copper mixtures, which have 11 groups.

The first trial that contained 10 mL of NaOH and 10 mL of CH3COOH produced a ΔHrxn of -13.11 kJ/m. The second trial, which contained 15 mL of NaOH and 5 mL of CH3COOH resulted in a ΔHrxn of -7.864 kJ/m. Based on the literature value of NaOH CH3COOH, -57.5 kJ/m, we were off by 44.39 kJ/m in the first trial, and 49.64 kJ/m in the second trial.

During this lab I learned how to convert the mass of a compound to the number of moles and then to the number of molecules, I also learned how to determine the concentration of a

The mass of salt (.26 grams) was then divided by the total mass of mixture (3 grams) and then multiplied by 100 to get 8.7% salt. The mass of sand was determined by subtracting the 100mL beaker with filter paper and sand (54.57 grams) by the the empty 100mL beaker with filter paper weighing 52.74 grams, to get 1.83 grams of sand. The mass percent of sand was determined by dividing the 1.83 grams of sand by the mass of mixture (3 grams) and multiplying by 100 to get 61%

The main purpose of the lab “Determination of the Formula of a Copper Oxide” was to determine the formula of a copper oxide. Specifically, this is a compound of copper combined with oxygen. This was to be done by heating the copper oxide thoroughly until all of the oxygen had been driven off. To accomplish this experiment, we first had to take and measure the mass of a specified color of copper oxide, ours being red. Then, we used a fischer burner to provide the heat needed for the split of copper oxide, in which our amount resided in a test tube. But, in order for the copper to not recombine with oxygen that could be found in the surrounding atmosphere of our lab, we also had to have a flow of methane gas into the test tube that fed into

We began this experiment by weighing out the known values of mass for 1-chloro-2,4-dinitrobenzene and m-aminobenzoic acid which was 1.012g and 0.686g respectively. These values were calculated before the experiement based on the mole ratios of the balanced equation in question. Here the reaction was a 1:1 ratio so we were able to determine the theoretical mass of our product, m-(2,4-dinitroanilino)

Identifying an unknown substance can be accomplished with the use of multiple scientific tests, which help narrow down the possibilities of the unknown compound. The unknown substance that I was given was unknown number A84841BIR, and posed to be a real challenge since I needed to test two different molecular combinations for this specific substance. Once the number of moles in substance was calculated using the ideal gas law, I divided it from the sample mass number after heating and obtained that the molarity of my unknown chemical was 58.93 g/mol. To find my molecular formula I calculated the mass of each element, then the moles, lastly I took the smallest whole-number ratio. Using the molarity calculated I was able to do some research to get a better understanding about what my unknown chemical could possibly be. Once I’ve collected all my data together and strenuously researched the web for articles relating to understanding Infa-Red spectroscopy, I should be able to make an educated guess upon what my unknown solution could be.

The Chemical Baggies Lab demonstrated to students how certain chemicals cause diverse chemical or physical changes depending on what substances were mixed together in a designed controlled experiment. During the process of this experiment, almost identical observations were made about different combinations of chemicals that had at least one substance in common. For example, the frequent observation that was made throughout the experiment was that heat was felt. Even though there were distinct chemical combinations, there was one substance that generated a certain observation or characteristic, such as a mixture has to comprise of the phenol red for there to be a color change, which was learned from this lab. Also, calcium chloride

Using the direct weighing and weighing by difference methods to find weight and mass of chemicals and compounds.

The purpose of this lab is to identify the unknown volatile liquid, by finding its molar mass and comparing it to the known molar masses. There are two ways to identify a possible molar mass, and they are to use the Kjeldahl method or the Dumas method (Simmone, Simmone, Eitenmiller, Mills & Cresman, 1997).