9. Theoretical yield = (150.22g/mol)(3.5 x 10^-3 mol of nucleophile) = 0.525 g Actual yield = 0.441 g, Percent Yield = (0.441g/0.525g) x 100% = 84% 10. Percent recovery from recrystallization = (0.172g/0.441g) x 100% = 38% 11. The data table provided below obtained melting point data for crude product, pure product, and mixture of the pure and 4-tert-butylbenzyl. 12.
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.
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.
Among Sodium, Zinc, Copper, Platinum, and Calcium, which element do you think is the hardest to extract electrons from? Explain. 2. Predict whether wavelength of a wave would play a role in the energy of the emitted electrons. Activity: 1.
In contrast, a substance that donates electrons is a reductant or reducing agent (Cao G, Prior RL, 1998). In general, a chemical reaction in which a substance gains electrons is defined as a reduction (SchaferFQ, BuettnerGR, 2001). Oxidation is a process in which a loss of electrons occurs. When a reductant donates its electrons, it causes another substance to be reduced, and, when an oxidant accepts electrons, it causes another substance to be oxidized (Hrbac J, Kohen R, 2000). In biology, a reducing agent acts via donation of electrons, usually by donation of hydrogen or removal of oxygen.
The CO2 gas produced can be used as an indicator for the rate of reaction as the amount of CO2 gas that is collected with in a fixed time is proportional to the rate of reaction. Therefore, the average rate of reaction can be calculated by measuring the amount of CO2 collected for a set period of time. The rate expression of the reaction is written as: rate = k[CaCO3]a[HCl]b 1 http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601032.html 2 http://www.thechemicalblog.co.uk/10-uses-of-hydrochloric-acid/ ￼Page 2 of 7 k represents the rate constant, a and b signify the order of reaction with respect to the reactants. The order of the reaction is the power to which the concentration of that reactant is raised to, for example, doubling the concentration of a reactant that is first order would double the rate of reaction while doubling the concentration of a reactant that is in the second order would quadruple the rate of reaction. TABLE OF VARIABLES ￼￼￼Independent Variable ￼￼￼￼￼￼￼Method of measurement ￼￼￼￼Concentration of HCl
In 1932 James Chadwick discovered a second particle in the nucleus, he fired alpha particles at beryllium and found that neutrons were released. He revised Bohr’s model of the atom to include a representation of both protons and neutrons in the visual diagram. Today we know that electrons orbit a nucleus made up of protons and neutrons and that the electrons can be described as both waves and
5. X-RAY DIFFRACTION * XRD is a technique generally employed for elucidation of structure and arrangement of atoms. * In our analysis the structure of GO and PCBGO were analysed. * The interlayer distance upon functionalisation can be seen as a function of oxidation. * The d spacing for GO= 7.82 Å from diffraction peak at 11.4 degrees for the  plane.
These metals have only one electron in their outer shell. This means they are ready to lose that one electron in ionic bonding with other elements. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals. Cesium and francium are the most reactive elements in this group.
John Townsend and Robert Millikan later on were able to determine their exact charge and mass. In 1911 Rutherford and German physicist Hans Geiger found out that electrons orbit the nucleus of an atom. Radiation is emitted during movement from one orbital to another. In 1945 Glenn Seaborg identified lanthanides and actinides , which are usually placed below the periodic table. Till this day, scientist are still trying to enhance their knowledge on the Periodic Table and its
Question # 1: Part A How many electrons and protons in an atom of vanadium? Answer # 1: Atomic number = number of protons = 23 Mass number = number of protons + neutrons Mass number = 51 g/mole Number of neutrons = 51-23 Number of Neutrons = 28 Number of electrons = atomic number = 23 Question # 1: Part B Explain in 2 or 3 sentences how the atomic weight is what is reported. Answer # 1: Atomic weight or atomic mass is basically the average mass of atoms of an element. Atomic mass is calculated by using the naturally occurring relative abundance of isotopes. Atomic weight determines the size of the atom.
Error Analysis We may have made a few errors along the way. We could have had a blunder because we may not have waited long enough for the penny to stay on the scale. We could have made a human error because we could have had a little more or less sodium hydroxide in our graduated cylinder and eyeballed it wrong. Another error you could have made was an instrumental limitations because read the cylinder wrong on the side by
Ytterbium is a rare earth metal, one of the elements found in Row 6 of the periodic table. It has an atomic number of 70, an atomic mass of 173.04, and a chemical symbol of Yb. Ytterbium is a typical metal that is both ductile and malleable. It has a melting point of 1,515°F (824°C), a boiling point of 2,600°F (1,427°C), and a density of 7.01 grams per cubic centimeter. Ytterbium is a relatively reactive element that is usually stored in sealed containers to prevent its reacting with oxygen of the air.