Melting point- Approximately half a spatula of each solid was placed in its own test tube. Using a test tube clamp, the test tubes containing the solids were gently heated one by one. Always remembering to keep the test tube moving in order to prevent overheating any one spot and pointing the mouth of the test tube away from yourself and others to avoid any unnecessary accidents. If the solid melts easily, record your results as low melting. If it does not melt, increase the time in the flame.
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.
This was accomplished using several different methods including filtration, sedimentation, decantation, extraction, and sublimation. In addition to carrying out some of these operations, we familiarized ourselves with both redox and metathesis reactions, two fundamental types of chemical reactions. Through these reactions, we performed several chemical transformations involving copper, and were able to recover our copper sample with maximum efficiency, thus accomplishing the objective of the experiment—to recover all of the copper with which we began. We performed the following chemical reactions: Cu ( s ) + 4 HNO3 ( aq ) → Cu( NO3 )2 ( aq ) + 2 NO2 ( g ) + 2 H2O ( l ) Redox [ i ] Cu( NO3 )2 ( aq ) + 2 NaOH ( aq ) → Cu( OH )2 ( s ) + 2 NaNO3 ( aq ) Metathesis [ ii ] Cu( OH )2 ( s ) → CuO ( s ) + H2O ( g ) Dehydration [ iii ] CuO ( s ) + H2SO4 ( aq ) → CuSO4 ( aq ) + H2O ( l ) Metathesis [ iv ] CuSO4 ( aq ) + Zn ( s ) → ZnSO4 ( aq ) + Cu ( s ) Redox [ v ] 3 CuSO4 ( aq ) + 2 Al ( s ) → Al2( SO4 )3 ( aq ) + 3 Cu ( s ) Redox [ vi ] While metathesis reactions proceed to completion whenever one of the components is removed from the solution (
We’re specifically looking into how much product will be created after conducting experiments with various different concentrations of Iodine and Zinc. One of the things we tested for was the production of a “white solid” which acted as our precipitate. Another key element we kept an eye out for was excess zinc, which showed us how much of the zinc was reacted. During our experiment we colleged exactly the amounts we needed for our group, no decimal point less! We also collected an accurate amount of acidified water, used to start the reaction.
This technique prevents the product to contact other reactants, and leave the heating environment which might cause side reactions. The removal of the product also helps to shift the equilibrium position of the incomplete reaction to the right hand side, and prevents backwards reaction, resulting in an increased yield of products. This experiment also introduces the idea of azeotrope. An azeotrope is a mixture of two or more pure compounds in such a ratio that its composition cannot be changed by simple distillation. This is because when an azeotrope is boiled, the resulting vapour has the same ratio of constituents as the original mixture of liquids.
Reactivity of Metals Background Information When a metal (such as magnesium, aluminium, zinc and copper) is mixed with hydrochloric acid, a hydrogen gas is produced. If hydrogen gas is produced, a pop sound should be heard when a flame is held over the substance. On the periodic table the most highly reactive elements are in the first group and the least reactive are in the last group. All metals have the same properties, they are shiny, they conduct heat and electricity, they are malleable which means able to change shape permanently without breaking or cracking, and they are also ductile which means they are able to be deformed without losing their strength. Aim To compare the reactivity of various metals by observing their reaction with hydrochloric acid Hypothesis That the all the metals will produce foam and a pop.
Focus Questions: 1) What happens Qualitatively on both the Macroscopic and Atomic levels when zinc, Iodine and Acidified Water are mixed? Does a Reaction Occur? On the Macroscopic Levels, there is no reaction. However, when Zinc and Iodine and Water are mixed together a color is formed in the solution and a release of heat occurs, an exothermic reaction. 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.
Second is the color of the laser light being more highly absorbed by the tattoo pigment than the surrounding skin. Thirdly, the time duration (pulse duration) of the laser energy must be very short, so that the tattoo pigment is heated to fragmentation temperature before its heat can dissipate to the surrounding skin. Otherwise, heating of the surrounding tissue can cause burns or scar. Lastly, sufficient energy must be delivered during each laser pulse to heat the pigment to fragmentation. If the energy is too low, pigment will not fragment and no removal will take place.” There are side effects to laser tattoo removal.
Unlike gas tungsten arc welding, which can’t be used outdoors because of the shielding gas issue, oxy-acetylene equipment can be used practically anywhere. Some Other advantages to oxy-fuel welding include the relatively low cost of equipment, the quick learning curve compared to gas tungsten arc welding methods, and the ability to easily regulate flame temperature by adjusting the gas flow. In oxy-fuel welding, a regulator is used to control the pressure from the tanks and into the hoses. The operator then adjusts the flow rate through a set of needle valves on the torch itself. It’s necessary to establish a constant inlet pressure into the hose, otherwise the needle valves won’t be able to provide accurate flow control, and poor welds will result.
When the gas comes out of the ground, it comes out wet. The first stage of the refining process involves on-site heating of the gas to 212 degrees to evaporate any non-methane hydrocarbons and fluids that are mixed into the gas. (Arthur, 2008) The condensate that is generated from this process is then vented into the atmosphere. The condensate often contains the same chemical additives that are added to the well during the fracking process, as well as volatile organic compounds that are naturally occurring in the ground where the gas is stored (Witter,