Name: ___________________________________ Date: ______________ Practice Test #3 ____ 1. When a precipitation reaction occurs, the ions that do not form the precipitate A) evaporate B) are cations only C) form a second insoluble compound in the solution D) are left dissolved in the solution E) none of these 2. An aqueous solution of potassium chloride is mixed with an aqueous solution of sodium nitrate. The complete ionic equation contains which of the following species (when balanced in standard form)? A) B) C) D) E) ____ 3.
Discussion: According to the observation, the original mixture separate to two points in both solvents. That means the original mixture contains two substances and the distances from the point to the starting line show the position of substance in this solvent. When the observations and positions of the original mixture were compared to the first and the second fractions, only one point part on first fraction under hexane solvent and the position of it is exact the same with the one in original mixture and there is also only one point on second fraction having the same position with the one in original mixture. It means that the samples we separated are pure enough to show only one pure point in each fraction under hexane solvent. Under toluene
Theoretically speaking, if we use one granule of zinc and one granule of iodine opposed to one granule of Barium Iodide and one granule of Zinc Sulfate, the cost would be $.2123 in total for the elemental reaction and $.9265 for the double replacement reaction. In terms of safety, it is safe to say that the safer thing would be centrifuging since we are
As long as the electronegativity difference is no greater than 1.7, the atoms can only share the bonding electrons. An example of a covalent bond would be water, its two hydrogen atoms with one oxygen atom (H2O). If two atoms differ considerably in their electronegativity than one of the atoms will lose its electron to the other atom. This results in a positively charged ion (cation) and negatively charged ion (anion). The bond between these two ions is called an ionic bond.If the electronegativity difference is greater than 1.7 then the higher electronegative atom has an electron attracting ability which is large enough to force the transfer of electrons from the lesser electronegative atom.
Purpose: The following lab was conducted in order to determine the iron (〖Fe〗^(2+)) content in an unknown sample by way of reduction-oxidation titration using a standardized potassium permanganate solution. Theory: Titration is one of the most commonly used methods for determining the amount or concentration of an unknown substance. Chemical analysis can be performed on redox titrations, if the following conditions are met: “The reaction is thermodynamically spontaneous enough to be stoichiometric”, “The reaction is kinetically fast enough to give operationally ‘instant’ results”, “No side reactions occur”, and “a satisfactory indicator exists”. These conditions are what makes potassium permanganate (〖KMnO〗_4) a very useful analytical oxidation agent as it easily fits the criteria. The half reactions for this system are: Oxidation of 〖Fe〗^(2+): 〖Fe〗^(2+)→ 〖Fe〗^(3+)+1e^- Reduction of 〖MnO〗_4^-: 〖MnO〗_4^-+8H_3 O^++5e^-→ 〖Mn〗^(2+)+12H_2 O Which produces the following overall equation: 〖MnO〗_4^-+8H_3 O^++5〖Fe〗^(2+)→5〖Fe〗^(3+)+〖Mn〗^(2+)+12H_2 O Equilibrium is initially obtained at a very slow rate, therefore the titration is carried out in the presence of excess sulphuric acid (H_2 〖SO〗_4) at a high temperature; in order to drastically increase the rate at which equilibrium is attained.
* X belongs to Group 2 of the periodic table because it has a low first and second ionization energy, however, a higher second and third. * b. What charge would you expect element X to have when it forms an ion? * Element X would form a positive charge because the first two would be kicked out and that would leave the two valence electrons forming an ion with +2 charge. * c. If you were to place elements X and Y into the periodic table, would element Y be in the same period as element X?
Appearance Iodine: silver sphere solid Zinc Shot: Round flat silver Zinc Granular: pencil shaving like silver solid Potassium iodide: white thick powder Focus Question: How well does the appearance and solubility of iodine and zinc respectively compare with information presented in the CRC Handbook of Chemistry and Physics? The appearance and solubility of iodine and zinc that we observed n the lab are very similar to the information presented in the CRC handbook of chemistry and physics. The iodine pieces we observed in lab were insoluble in water, and soluble in potassium iodide (very soluble), mineral oil (slightly soluble), and alcohol (slightly soluble). This consigns with what the CSC handbook stated that’s potassium iodide,
Abdul Gadoush Period 2 Chemistry Honors 1-16-14 Metal Gizmo 1. Purpose/Problem: The whole purpose to this experiment was to identify which metal of the following: Copper, Magnesium or zinc had the most occurring reactions in the constant chemicals that they were inserted in. The metal that had the least amount of reactions in each chemical would be the least reactant, and the metal that had the most occurring reactions in the chemical would be the most reactant. For this process to occur (make metal gizmos), Naugatuck Metal Works needs one highly reactive metal and another that isn't a reactive metal. - signs of chemical change = changes the shape and color, creates a gas, distributes heat, Etc.