high melting point, hard, brittle, slightly soluble in water, conductor of electricity when melted or in solution Molecular solid - crystalline solid that has molecules arranged in a particular configuration. low melting point, generally insoluble in water, nonconductor of electricity. Metallic solid - crystalline solid that has atoms of metals arranged in a definite pattern. low to high melting point, malleable, ductile, conductor of electricity, insoluble in most solvents. Lesson 13.6 Changes of physical state: * necessary to draw a temperature-energy graph to see the change in temperature with a constant application of heat Heat of fusion - the amount of heat required to melt 1.00 g of substance.
The chart of reactivity tells chemists the comparable reactivity of elements. An element higher on the list is more reactive than the elements below it and can replace all elements below it. Overall, knowing the types of reactions and reactivity of elements both help predict products of a reaction. It is only with an understanding of these principles can one execute the Copper Cycle Experiment, for the experiment requires a good understanding of how mass can be altered via these reactions, but never destroyed. The experiment was performed to evaluate the skills of an individual to perform some lab skills like filtration and decantation and use these skills to understand the concept of percent yield.
Reaction rate is affected by any catalysts present (which speed up the reaction usually with an intermediate step), temperature (increases the number of particles collisions), concentration (increases the number of collisions), and surface area (increases the space available for collisions). Reactions can only occur when collisions take place. The most generic form of the rate law is Rate = K * [A]m * [B]n where (k is a constant specific to an equation and temperature). Now, the compounds A and B might not have any effect on the rate, which would cause them to drop out of the equation completely, or they might have so much effect that they are raised an order (squaring the concentration). The rate law for this reaction is k [CV+]m[OH-]n. Since the hydroxide ion concentration at the beginning is about 1000 times larger than the concentration of crystal violet, [OH-] will not change that much during this
If it does not melt, increase the time in the flame. If the solid melts under this increased heating, record it as medium melting. In the event the solid does not melt, record it as high melting. 3. Solubility- First, the solubility test was carried out in distilled water.
In our lab we use a more sophisticated one which included a lid on the cup with an inserted thermometer and a stirrer. Thermochemistry is the study of the heat released or absorbed as a result of chemical reactions. The measurement of the total energy of a thermodynamic reaction is called enthalpy (q). This is the basis for Hess’s law which states that if two reactions are combined to yield a third reaction, the sum of the first two is equal to the third. The energy change is the same whether the process occurs in one step or many.
1) Jeffrey Cox CHE111-DL01 Lab number 10 Stoichiometry of a Precipitation Reaction 2) Purpose/ Intro. In this lab we will be able to calculate the actual, theoretical, and percent yield of the product from a precipitation reaction. We will thusly learn the concepts of solubility and the formation of a precipitate. A precipitate reaction is a reaction in which soluble ions in separate solutions are mixed together to form an insoluble compound that settles out of the combined solution as a solid. The solid then is the insoluble compound, called a precipitate.
Once a solute is added to the solvent, solute molecules occupy the molecular surface space of the liquid, swing the evaporation process. If the solute is dissolved in a solvent, the number of solvent molecules near the surface decreases, thus vapor pressure of the solvent decreases. Why does this property change when the solute is increased? One use for vapor pressure lowering is in distillation. Distillation is a liquid purification process using heating and cooling.
Occasionally, magnesium will substitute for iron, and aluminum and ferric ions will substitute for chromium. In this experiment we will hope to figure out whether or not the unknown sample contains the very important mineral Chromite. The experiment will consist of a process called hydrometallurgy. Hydrometallurgy is a technique that uses aqueous solution chemistry to recover metals from minerals, ores and salts. Extracting the metal from the solution is the first step in the process of hydrometallurgy.
ii) liquids > vibrating particles have sufficient energy to move from their fixed positions to other parts within a liquid. > liquids take the shape of their container. iii) gases > particles have sufficient kinetic energy to help escape the attractive forces from other particles. > gases take up the complete volume of a container. The kinetic theory provides vital information on the sciences we learn.
The color starts out as a reddish brown color, and then, when swirled, becomes a gold yellowish color, and slowly becomes transparent clear at the end of the reaction. As Zinc and Iodine is reacting, the bottom of the test tube would become hot, but slowly, about 5-10 minutes, will begin to cool down to room temperature. On the atomic levels, the atoms of both Zinc and Iodine are reacting causing that exothermic reaction to occur. The atoms would combine together to form ZnI2, and cause a color change because of the interaction between the particles. When the water is evaporated, a white compound of zinc iodide is formed.