Essay On Stoichiometry

Combustion Reaction: A chemical reaction between a fuel and an oxidizing agent that produces heat.

10. The accepted value for the density of aluminum is 2.699 g/cm3. Using this density and the masses of your two samples of aluminum foil, calculate the volume of aluminum in each sample: the regular vs. the heavy duty. (Note: You will have to use a bit of algebra and the formula D = m/v for this calculation!)  You must show all your work. (15 pts)

The mass percent of ascorbic acid in the sample is given by dividing the calculated mass of ascorbic acid (0.414060408 g) by the calculated mass of the sample (0.5500 g) and multiplying the quotient by 100%.

The weight of each 50ml beaker (used for weighing the mass of dissolved Potassium chloride after the evaporation of water) should be recorded. If the experimenter were to weigh the mass of one beaker and take it as a default mass, the latter may be a source of error.

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.

Measure 500ml of tap water in the 500cm3 beaker, then measure 5g of sodium hydrogen carbonate using the 50cm3 beaker and weight scale and place in the beaker of water, using the glass rod to dissolve it into the mixture.

Usually, the percent is a good amount less than 100 because of multiple factors including transfer between different lab tools and when an unfulfilled reaction takes place. In the case of this experiment, copper most likely was lost between transfers of the Copper (II) solution, although loss was attempted to be minimized. Also, after the reaction, the copper was filtered and some mass could have lost if the reaction was not fully carried out and all of the copper did not precipitate out of the solution. But, when the copper oxidized overnight on the heater, the reaction with oxygen added mass to the ending mass of copper. These areas of losing and gaining mass throughout the procedure equaled out in the end because the percent yield was very close to 100% as the actual yield was 0.7 grams of copper and the theoretical yield was 0.71 grams of copper. If the copper did not oxidize, it is believed that the percent yield would not have been as close to 100% as it was because the oxygen gave mass back that was lost along the way of the

5. Calculate the mass of the water by subtracting “Mass A” from “Mass B.” Record the mass of the water in Data Table 4.

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).

Your mass precision should be reported to a thousandth of a gram, i.e. 0.302. (Use 3 significant figures.)

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.

1) Pour 25 mL of the 1 M hydrochloric acid into the beaker and rinse the solid by swirling the acid around in the bottom of the beaker.

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.

This purpose of this experiment is to calculate the thickness of a sheet of aluminum foil. This experiment is necessary because the human eye cannot accurately measure the small thickness of aluminum foil with only a ruler. However, to understand the procedure one needs to understand conversion, density, and volume. Conversion is when one converts one unit to another unit using a conversion factor(e.g. 2.54cm/in). Density is how much mass there is in a certain volume(density=mass/volume) and it stays constant in a substances and mixtures that have the same composition. Volume is the amount of space that an object occupies. The experiment will consist of weighing of aluminum foil, measuring the length and width, then converting these values

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.