Dumas Method

Purpose: To learn about the international system of units (SI), to become familiar with common lab equipment and techniques, to gain proficiency in determining volume, mass, length, and temperature of a variety of items using common laboratory measurement devices, to learn to combine units to determine density and concentration, and to use laboratory equipment to create serial dilutions and determine the density and concentration of each dilution.

Mole of chlorine : 1.0217g - .221g - .3946 g = .4061 g of chlorine

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

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).

For q, you found how much heat was gained by the water so you know that same amount of heat was lost by the metal. Therefore, qmetal = -qwater. The mass of the sample was recorded from the baggie. The temperature change

3. The volume of a fixed mass of a liquid sample increases as the temperature rises from 20 to

It used mass, temperature, length, volume, density, and making a dilute solution. I learned the importance as well as the difficulty of making proper measurements in a lab setting. If one measurement is off, it will throw the entire equation off. This will give either incorrect or inaccurate results.

15. Determine the mass of the water by using the water’s density (specific to the initial temperature) and the volume of the water. Remember, density = mass/volume. You can look up the density of the water at your specific temperature at

Lab 1 also teaches us the importance of molecular weight of a substance and how to use that to find the amount of moles of that substance in a solution. For example; in exercise 3 we were asked to weigh 8 grams of sugar and then calculate how many moles of sugar it really was. Using the molecular weight of sugar (C = 12.01 grams/mol, H = 1.008 grams/mole, O = 15.00 grams/mole). We were then able to use this molecular mass of the sugar that we then had to use to calculate and determine the molarity of the sugar

I think I have lots of accomplishments. I have learned so many ways to make my argument and get your point across. I have learned how to approach a topic. My most significant accomplishment that is Toulmin’s and Rogerian method really helps a lot. In fact this is my new approach in dealing with argument. Toulmin’s and Rogerian method help me a lot to develop my arguments, and I believe this model will help lots of people too. My area of weakness are to be able to explain my argument in details. I think is a gradual process but with hardworking and continuous effort, I will be a good writer. Also some of my work are submitted close to the due time, due to my work and other class I combined together, but I will try to improve

The guiding question of this ADI lab was, “What are the identities of the unknown compounds?” The goal of this lab was to understand the relationships between moles and molar mass to find the identity of unknown compounds. The mole can be used to measure small amounts of a substance or is used to convert from unit to unit using dimensional analysis. One mole is equivalent to the molar mass in grams of that substance. If you start with the moles of an unknown substance, multiply it by a given compound’s molar mass, and then divide it by however many moles are in the compound of your choice, you will get the mass of the compound. With that answer you can then compare with mass of the compound in the bag to determine its identity. We first started

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

One milliliter of 6.00-M phosphoric acid was placed into a 125-mL Erlenmeyer flask using a volumetric pipette. Using a slightly larger pipette, six milliliters of 3.00-M sodium hydroxide was transferred into a 50-mL beaker. Then a disposable pipette was used to slowly mix the sodium hydroxide into the phosphoric acid while the solution was swirled around. Then both the beaker and flask were rinsed with 2-mL of deionized water and set aside. A clean and dry evaporating dish was weighed with watch glass on a scale. Then the solution was poured into the dish and the watch glass was placed on top. The solution was then heated with a Bunsen burner to allow for the water to boil off to reveal a dry white solid. After the dish cooled to room temperature it was once again weighed and the new mass was recorded.

After that, it is crucial to convert the mass to volume. The water density at a temperature will aid this process. The compliance of the Volume Occupied by 1.000g of Water Weigh in Air table is deemed necessary throughout the comparison.

If the mass of the reactants are compared to the mass of the products, then the mass will stay the same because the law of conservation of mass states that in any given chemical reaction, the total mass of the reactants equals the total mass of the products.