C is plotted and fitted to a logarithmic-line to illustrate the saturation effect, shown in Figure 1. Then using equation 12.8 in the lab manual, C/Y is calculated and plotted versus C and fitted to a straight line, shown in Figure 2. From the fitted line, Ymax, which is the maximum number of moles of acetic acid that can be adsorbed on the surface of the charcoal per gram of charcoal, can be calculated from the slope. Then, using Ymax and the value of the y-intercept, K, which is the ratio between the rate constant k1 of the forward reaction (adsorption on the charcoal) and the rate constant k-1 (detachment from the charcoal), can be determined. For calculations, refer to Appendix E. Finally, multiplying Ymax by Avagadro’s number will give the number of AA molecules adsorbed on the surface of one gram of charcoal at saturation.
Introduction During this experiment, the mass of copper was weighed in grams. It was measured with sodium hydroxide, sulfuric acid, zinc, hydrochloric acid, methanol, and acetone. The main instruments used in this experiment was a balance, beaker, stirring rod, evaporating dish, wire gauze, ring stand, graduated cylinder, copper wire, nitric acid, hydrochloric acid, water, sodium hydroxide, zinc, sulfuric acid, and a hot plate. By finding the raw data, the percent recovered was able to be calculated. Theory The equation that was used in this experiment is % recovered = 100% X m/m0.
Estimation of superoxide dismutase (SOD) activity 246 SOD activity was estimated by its ability to catalyse NBT to formazan at 560nm 247 according to the method of Beyer and Fridovich (40). Five ml of reaction mixture 248 containing 50 mm phosphate buffer (pH 7.8), 13 mm methionine, 75 mm NBT, 2 mm 249 riboflavin, 0.1 mm EDTA and the enzyme extract. Absorbance of sample was read at 560 250 nm. The difference of percentage reduction of colour development in blank and the 251 sample was calculated. Fifty percent reduction in the colour was taken as one unit of 252 enzyme activity and was expressed in enzyme units per milligram protein (U mg-1 253 protein).
Copper has a blue-green oxidized surface. The Statue of Liberty is a prime example of oxidized copper. The oxidized surface consists of insoluble ionic compounds of copper (II) oxide and copper (II) carbonate. In class, we did an experiment with where we changed copper into its different states. For example, we added sodium hydroxide to copper (II) nitrate.
Calculations: how did we calculate and determine the mass of magnesium oxide? we Determined the mass of MgO (magnesium oxide) by subtracting the mass of the crucible with lid on from the mass, weight of the crucible with lid, and magnesium oxide. then in order to determine the oxygen mass, we will subtract the mass of the magnesium from the mg oxide to find out the amount of magnesium in the compound, divide the mass of Magnesium ( numbers of grams in one mole of magnesium we did the same way to find the amount of oxygen, where we divided the mass weight of oxygen with the numbers of grams in one mole of oxygen. and lastly in order to determine the empirical formula of magnesium oxide we Used the molar ratio to determined it. mass of Mg= o.122g mass of magnesium oxide=0.25 mass of magnesium oxide - mass of Mg + mass of O 0.25g= 0.122g + mass of O mass of O = 0.25g- 0.122g = 0.128g moles of Mg = 0.122g x 1 mol of Mg divided 24.30g Mg ( mass of magnesium) = 0.122 mol Mg moles of O = 0.25g O x 1 mol of O divided by 16g of O = 0.25 mol o the ratio = 1:1 there is one mol for mg for one mol of O, therefore there will be 1 atom of mg for 1 mol of oxygen.
A magnesium atom has a charge of 2+ and an oxygen atom has a charge of 2-. When the charges are balanced, the equation is MgO, one magnesium atom joined in an ionic bond with one oxygen atom. With the theoretical empirical formula found, one can now find the theoretical percent composition of MgO. The atomic molar mass of a magnesium atom is 24.31 g/mol and 16.00 g/mol for oxygen, therefore the total theoretical mass of the compound is (24.31 g/mol + 16.00 g/mol) 40.31 g/mol. The percent composition is found by dividing the element’s mass by the total mass of the
This helps to indicate whether or not the reaction follows Markovnikov’s Rule, which states that the electrophile (E+) will add to the carbon involved in a double bond that produces the most stable carbocation. If the rule is followed, the reaction will proceed according to the mechanism in Figure 1. In the silver nitrate test, the alkyl bromide is added to AgNO3. The rate of precipitation with 2° should be faster than the solution with the 1° alkyl halide. In the sodium iodide test, the alkyl halide is added to sodium iodide in acetone.
This was approached by finding the molar mass of sodium thiosulfate pentahydrate and then using that value to convert the grams of the sodium thiosulfate used for the initial creation of the weigh bure into moles. The molar mass of sodium thiosulfate pentahydrate was found by adding the atomic masses of each element found in the compound, as shown in Example 1. The molar mass was then used to convert the grams used into moles by using dimensional analysis. Example 1: Na2S2O35H2O (22.990Nag x 2)+(32.066Sg x 2)+(15.999Og x 3)+(1.008Hg x 10)+(15.999Og x 5)= 248.18 g/mol Example 2: 0.21gx1 mol248.18 g= 8.46 x 10-4 mol The last step in completing the Preparation Table was to calculate the concentration of the standard thiosulfate solution by dividing the moles of sodium thiosulfate pentahydrate by the mass of the solution, in grams(Example 3). Example 3: 8.46 x 10-4 moles of Na2S2O35H2O/ 9.70 grams of solution = 8.72 x 10-5
2. Explain how to determine the formula mass (mole mass) for a compound. Molar mass is the mass (in grams) of one mole of a substance. Using the atomic mass of an element and multiplying it by the conversion factor grams per mole (g/mol), you can calculate the molar mass of that element. First, find the chemical formula for the compound.
Sulphur is a yellowish, non-metallic chemical element in the periodic table. It is found in group 6 and period 3. Sulphur is identified by the letter S. Since Sulphur is the 16th Element of the periodic table therefore atomic number is always similar as the proton number which is located in the nucleus and converts the nucleus in to a positive charge as neutron is a neutral charge (+-) so positive (+) plus neutral (+-) equals a positive charge. The atomic mass for sulphur is 32 amu or (Atomic Mass Unit is the international system of units). The melting point of sulphur is 112.8 °C and the boiling point of Sulphur is 444.6 °C.