Calorimetry Lab

During this investigation the question we looked to answer was: what are the identities of the unknown compounds? In an effort to answer the question, our group designed a method in which the relationships between the unknown compounds in plastic bags were compared so that their identities could be determined. The mole (mol) provides a measure of the number of atoms present in the sample of a compound. One mole of an element or compound contains

Percent Recovery of Components Compound Aspirin Caffeine Salicylamide Actual Mass (g) 0.671 0.052 0.283 Expected Mass (g) 1.300 0.0666 0.390 Percent Yeild (%) 52% 78% 73%

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).

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

This experiment was performed to observe differences in density based on the chemical makeup of an object. Pennies minted before 1982, pennies minted after 1982, and an unknown metal sample was tested to see if there were any differences in their densities. Ten pennies from each category and the metal sample were weighed using a scale to find mass and the displacement method was used to find their volumes. The masses and volumes were then used to calculate the densities of the pennies (D=m/v). The density of the pre-1982 pennies were 8.6 g/mL while the post-1982 pennies were 6.9 g/mL. The metal sample’s density was 1.7 g/mL. Following the experiment we were given the real densities of each item to calculate the percent error with the formula

The purpose of this lab was to become familiar with the three different balances and two different methods used to find the weight and mass of chemicals and compounds in the ChemLab program. The lab was performed by using three different types of balances, and the direct weighing and weighing by difference methods.

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).

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.

In the first part of the experiment (identifying the chemical makeup of the unknown compound

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.

The order of steps were determined by which solids did not have to be mixed with water and which solids had to be mixed with water. So the first steps were determined if there were any magnetic materials in the mixture; which the iron filings were. The best first step would have been to separate the large materials from the small materials (the bird seed would be separated from the sand, salt, and iron filings) using a sifter so that all the salt, sand and iron filings can be found easily and nothing is sticking to the seed. Then measure the mass of the bird seed in a souffle cup. The second steps determined were by size because if the larger material, such as bird seed got wet, then the result of recovered mass would be harder to determine

The mass of the individual recovered components make up the total mass of the 1:1:1 mixture of Benzoic acid, Benzocaine, and Fluorenone. Because the ratio is 1:1:1, that means all of the components are equally weighted in the total weight of the mixture. Since the starting weight of the 1:1:1 heterogeneous mixture was 0.618 g, you can assume that the 0.618 g is made up of the three components each weighing 0.206 g. This came from dividing the starting weight by 3, since there are three components. As shown in the percent recovery calculations above the percent recovery of benzoic acid was 60.6 %, the percent recovery of benzocaine was 62.2% and the percent recovery of fluorenone was 59.7%. These percent recoveries are reasonable for the mixture

I took out the flask and scraped out the solid and weighed it on the analytical

Data Can be divided into two groups, qualitative data and quantitate data, on one hand we have qualitative data which is the type of data that observed rather than calculated numerically and on the other hand we have quantitative data which is the opposite of the latter where it is measured numerically and is expressed in numbers. within this experiment we explored both parts of data and collected both for each reaction we made in lab and thanks to gravimetric stoichiometry we are able to determine percent mass changes that occur in each reaction due to the simple fact that in a chemical reaction the mass is never lost its only transformed, therefore we are able to make assumptions on stoichiometry as a whole and