Energetics Aim: To measure the energy released from the complete combustion of a known mass of alcohol or paraffin wax, to heat water. Hypothesis: The combustion of alcohols is exothermic. In this experiment the energy is released from burning a known mass of alcohol in order to heat a known amount of water. A comparison of various alcohols and paraffin wax (methanol, ethanol, propanol, butanol, octanol and candle) as fuels can be made by calculating the quantity of energy transferred to the water. In this experiment, the amount of energy (heat) involved in a chemical change will be determined.
Simple and Fractional Distillation of Cyclohexane and Toluene Purpose: The purpose of this experiment was to become familiar with the processes of simple and fractional distillation. In this experiment a mixture of two volatile compounds, cyclohexane and toluene, were separated with the process of distillation. Distillation relies on each compound having distinct and separate boiling points. The pure products were analyzed with gas chromatography to determine the success of the distillation. Introduction: Distillation is the process of heating a liquid until it boils, then condensing and collecting the resulting hot vapors.
In the experiment a secondary alcohol (cyclohexanol) is heated with acid (phosphoric acid). A carbocation is generated by the loss of water from cyclohexanol because of the protonated alcohol. Loss of hydrogen ion from the carbocation will give the desired alkene (cyclohexene). Fractional distillation is used to separate liquids that have different boiling points that are relatively close together. By using this method of distillation a mixture is heated to a temperature at which several fractions of the compound is evaporated the distillate is then condensed and collected.
There is still carbon dioxide gas dissolved in the liquid at atmospheric pressure. The amount is very small and depends on temperature. It would be interesting to try this experiment again with a cold bottle and a warm bottle. Because carbon dioxide affects the pH of the soda it might be interesting to compare the pH of the fresh out of the bottle and the "defizzed" soda. What is the pressure that is used to put the carbon dioxide into the bottle in the first place?
Thermal runaway reaction occurs when the heat generated by a reaction goes beyond the heat removal caused by the available cooling capacity. Heat is accumulated leading to a gradual rise in the temperature of the reaction mass; this causes an increase to the rate of reaction and increases the speed of rate of heat generation. [1] Why are thermal runaway reactions dangerous on industrial scale? Thermal runaway reactions are always said to be dangerous on an industrial scale since the reactions go faster in an industry where they tend to reach higher temperatures. As you would already know that exothermic reactions tend to release quite a large amount of heat, so when the reaction mixture gets very warm, a very hot exothermic reaction begins.
Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your prediction? The increase of flow tube radius increased the flow rate, as predicted. 3. Describe the effect that radius changes have on the laminar flow of a fluid.
For this particular exercise, you should be familiar with the following: • Sublimation: Many chemicals will sublime (phase change from solid state to gas state) provided the right conditions. Iodine, for example, sublimes at room temperature. A bottle of iodine will thus always have crystals forming around inside the bottle around the cap where sublimed iodine is being deposited (phase change from gas state back to solid state). Provided the proper equipment, chemicals that are being sublimed can be recovered. Decant(ing): Decanting is a way of separating a solid from a liquid.
Distillation: Separation and Purification of Organic Liquids Boiling Point & Distillation Theory & Background Boiling Point ~ Temperature at which a liquid phase transitions into a gas phase, also known as vapor ~Temperature at which the vapor pressure of a pure liquid becomes equal to the pressure exerted by its surroundings Vapor Pressure ~Pressure exerted when molecules in the vapor strike the walls of the container in which the liquid is maintained ~Increase in vapor pressure occurs as there is an increase in temperature Distillation ~Technique used to purify and separate liquids by reaching their boiling points and condensing them to collect the condensate Continued Boiling Point Fractions ~First Fraction (First Cut)- is the first material to distill which is rich in the more volatile or lowerboiling component ~Last Fraction (Last Cut)- is the last material to distill which is less volatile or a higher-boiling component Continued Uses ~Identifying Compounds ~Purification of Compounds Boiling Point & Distillation ~A pure substance can be identified by reaching its boiling point and then condensing it ~Mixed Compounds can be purified by using fractionating columns that condense and separate liquids when they reach their boiling points and become insoluble in their vapor phases with each other ~Fractionating columns can separate liquids with boiling points of 2 degrees celsius difference, although they are not a 100% efficient In the experiment 1. Distill pure hexane by simple distillation, and record the boiling point. 2. Distill a mixture of 10 mL of hexane and 10 mL of toluene by simple distillation, and record the changes of temperature. 3.
This means that if the pressure on the gas increases, the volume decreases proportionally; conversely, if the pressure decreses, the volume increases. Doubling the pressure cuts the volume in half; tripling the pressure reduces the volume to one-third its original value; quadrupling the pressure reduces the volume to one-fourth its original value. The mathematical equation for Boyle’s law is P1 x V1 = P2 X V2 Boyle’s law is consistent with kinetic molecular theory. The pressure that a gas exerts results from collisions of the gas molecules with the sides of the container. If the volume of a container holding a specific number of gas is increased, the total wall area of the container will also increase, and the nu Charles’s law p 170 The relationship between the temperature and the volume of a gas at constant pressure is called Charles’s law after the French scientist Jacques Charles.
It expands when its temperature rises above 4° C. (39° F.). It also expands when it freezes. Expansion of Gases Under equal pressures, all gases expand at the same rate. A gas expands by the same proportion as the temperature rises, provided external pressure remains the same. The effect of heat on the expansion of gases is stated in Charles' Law.