Calorimetry Lab Report

The purpose of this lab is to figure out the mass percentage of copper in a penny. Furthermore, by doing this lab we will practice using a spectrophotometer and review the names of equipment such as volumetric glassware, pipets, and volumetric flasks.

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.

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

In a chemistry stockroom, a vial of an Unknown White Compound was found. In order to properly dispose of the substance, the substance has to be identified .The possible compounds has been limited to one of 15 different compounds. Also, approximately 5 grams of the Unknown White Compound (UWC) were available for testing. In order to determine the properties of the compound, a series of tests was conducted. These tests included a ph test, a conductivity test, a flame test, a sulfate test, a halide test, an ammonium test, a solubility test, and a carbonate test. Using the results of these experiments, it was hypothesized that the UWC is potassium chloride. To further confirm the hypothesis, a synthesis of potassium chloride was conducted.

Unknown white compound (823U) was discovered in the lab. In order to dispose of it correctly, the substance and its physical and chemical properties had to be identified. The unknown white compound was one of a list of 15 compounds. 5g of the unknown compound were given in order to correctly identify and discover its physical and chemical properties. In order to do so, a solubility test, a flame test, and ion tests were conducted. From the results of these initial tests and the given list of compounds, the unknown white compound was thought to be composed of sodium and a halide (I-, Br-, or Cl-). Of the list, NaCl was the appropriate compound, however NaC2H3O3 was also tested out of skepticism. To verify the identity of the substance, the solubility and flame tests were performed again along with a pH test. The pH tests of NaCl and NaC2H3O2 did not match that of the unknown white compound. The list of compounds had been entirely ruled out. The identity of the unknown white compound was revealed to be calcium chloride. To synthesize at least a gram (calculated to produce 1.2g) of CaCl2, the following reaction was completed.

The purpose of this experiment was to determine the composition of an unknown cylindrical solid using the property of density. The lab reinforced the formula that p, or density, is equal to mass divided by volume and that the volume of a cylinder is equal to (πr2h)/4. Therefore, the density formula of a cylinder, p=(4m)/(πd2l), was used to calculate the density of the solid, which was computed to be 7.16 g/cm3. After determining this value and doing further research, the group concluded the metal’s unknown composition to be chromium, which has a density of 7.19 g/cm3. The measurements related to the density of the cylinder required obtaining three types of average measurements, in which each of these had some inherent error. The

1. In the human blood, there is the bicarbonate buffer system. CO2 is released from cellular respiration and then taken up by red blood cells. Next, it is changed to carbonic acid which dissociates to form bicarbonate and H+ ions.

1. 100 + 273 K = 373 K 150 + 273 K = 423 K 960 L x 423 K / 373 K = 1,089 L 2.

The purpose of this experiment is to verify the formula of magnesium oxide based on the masses of magnesium and the product (MgO). We verify the formula firstly by calculating the empirical formula of magnesium oxide and then calculating creating the magnesium oxide itself- a magnesium ribbon is combined with oxygen in the presence of air through combustion and this forms MgO. The empirical formula of a compound is the simplest method of expressing a chemical formula in whole-number ratios of the constituent atoms that are consistent with masses measured in the experiment; whereas the molecular formula expresses the chemical formula using the actual number of atoms. For example, the molecular formula of anthracene is C14H10 while the empirical formula is C7H5.

Identifying this organic acid was an extensive task that involved several different experiments. Firstly, the melting point had to be determined. Since melting point can be determined to an almost exact degree, finding a close melting point of the specific unknown can accurately point to the identification of the acid. In this case the best melting point

The mass spectrometry can also show each isotope, elements that differ only in the neutrons, because it is sensitive enough to differentiate between different ions. By analyzing the information given by the mass spectroscopy, unknown molecule can

In this lab a cotton swab was fluffed up by scraping it against the serrated edge of a tape dispenser and then dipped into a liquid chemical solution. Once dipped the cotton swab was placed horizontally above the fire making sure to only burn the cotton part so as to not accidently get a different flame because of the burning stick. The color of the flame is viewed through a spectroscope and then both that spectrum and the color to the naked eye are recorded on a data table. This step is repeated for the remaining four solutions and then the bunsen burner is turned off and the area is cleaned. The purpose of this lab was to observe the relationship between various elements and emission spectroscopy and identify an unknown substance. By burning

Have you ever wondered why a fire burns orange, or why a lighter burns blue towards the bottom of the flame? If we take a quick step back, this is mostly due to a chemical reaction that is known as the “specific heat”. This must be achieved (as well as the other two properties that every fire is required to possess in order to burn) in order for a flame to become present. After this specific heat is reached, a chemical reaction occurs and turns the fuel source of the fire into a vapor. The aspects that are required for a flame to be created are a heat source, some sort of fuel, as well as some sort of oxidizing agent. The only way that a change in flame color can be observed is by manipulating the fuel source. After we manipulate the source

The molar mass of unknown one at 0.2252 g is 248.29 g/mol, at 0.2252 g it is 248.29 g/mol, and at 0.2482 g, it is 91.25 g/mol. The average molar mass calculated is 205.07 g/mol. There was a jump in the molar mass value at different weight. This could have been due to the experimental errors that occurred during the lab. The graph of the solvent solution initially begins at 23.8˚C but jump down to 10.5˚C. This makes a huge impact on the results of the data because the freezing point should start earlier in time than it shows in the data sheet.

where p is the density, g is the acceleration due to gravity, h is the height of the solution and r is the radius of the capillary.