The collected crude caffeine is washed with ethanol and heated in a water bath until the caffeine has completely dissolved in the ethanol.The water soluble materials in the tea leaves are extracted into hot water.The hot solution is allowed to cool and the caffeine is then extracted from the water with dichloromethane (methylene chloride), which is an organic solvent that is insoluble in water.The leaves are then returned to the bags and boiled for 5 minutes in 100 mL of distilled water in a 250 mL beaker with a cover (a watch glass may do).The group was tasked to take 5 bags of commercially sold tea (caffeinated) and to boil for 5 minutes in water to extract the water soluble materials in the tea leaves into hot water which in this case...
1475 words (3.7 pages)
.. Possible errors that could have occurred during the experiment are: the solid didn’t dissolve properly, temperature could have been wrong during the cooling down process, the recrystallization of the ammonium chloride in water was difficult to judge and malfunction of equipment could have caused errors.Salt and sugar both dissolve in water easily because their molecules are attracted to the small electrical charges of water.This 10mL of water was added to the large clean test tube with the solid ammonium chloride.In this experiment the controlled variable will be 10mL of water that is added to each test tube filled with ammonium chloride... One way to possibly improve the experiment is to use the exact amount of water to get a measu...
3142 words (7.9 pages)
The Craig tube was plugged and set in an Erlenmeyer flask to cool.The tube was then centrifuged for 3 minutes to remove the liquid.Cooling the mixture in an ice bath ensures that all crystals have formed, and drying removes any remaining solvent.Acetaminophen crystallizes slowly, so cooling the mixture adequately is necessary.All of the solid was dissolved in the hot solvent, and crystallization occurred once induced by scratching the inside of the tube.
1069 words (2.7 pages)
-On rear-wheel-drive vehicles,the water pup is located between the engine block and engine fan.On a few front-wheel-drive vehicles,the water pump is located at the rear of the engine.The water pump, uses centrifugal force to circulate the coolant,and consists of a fan shaped impeller set in a round chamber with curved inlet and outlet passages.The chamber is called a scroll because of the curved areas.The centrifugal design causes vehicles increase engine speed when the coolant temperature begin to rise.-Core plugs seal the holes used during the manufacturing process.The plugs are round discs of sheet metal pressed into openings on the side of the engine block that lead directly into the water jackets.These plugs may leak or pop out if t...
2503 words (6.3 pages)
Engine cooling system is a system that responsible for cooling the engine by releasing heat through the cooling fins so that the carâ€™s engine is not too hot or not too cold.The pressure drops sharply at the inlet/outlet of the water pump during the operational of the water engines and this pressure drop will vary in proportion to the rotational speed.So, while providing freeze protection and an increased boiling point, ethylene glycol lowers the specific heat capacity of water mixtures relative to pure water.It is not recommended to use only water as a liquid cooling because it would freeze if the temperature drop below 0oC.Tap water contains magnesium and calcium ions that will form the yellow precipitate (rust) when the water becomes...
5186 words (13.0 pages)
The water that condenses on the evaporator in an air conditioner is usually routed thorough a drain channel to the outside of the window, thus removing extracted water from the conditioned space.If water is left to stand in a tube for an extended period, the chemical characteristics of the water change as the mixed scale and corrosion products are deposited.Unlike closed-cycle refrigeration, evaporative cooling requires a water source, and must continually consume water to operate.The effect of the water chemistry can be empirically determined though use of the Pitting Propensity Rating (PPR) a number that takes into account the sulfate, chloride,nitrate and sodium ion concentrations of the water as well as its acidity or pH.This improvi...
4179 words (10.4 pages)
Salt rejection = Where Cf is the conductivity of feed water and Cp is the conductivity of the permeate water.Heat exchanger: the evaporated water from the boiler is passed through the heat exchanger where it loses heat to the working fluid/feed water in the heat exchanger.The rejected water is passed through another filter that further removes clean water.This is shown in figure 4 below Figure 4 Increasing the feed water and the feed water circulation path.Figure 3 showing the suggested improvement changing the shell and tube heat exchanger into a four pass boiler allowing the feed water to extract more heat from the steam during distillation Another method of increasing the cooling efficiency is to increase both baffles and the number...
1632 words (4.1 pages)
Replace the test tube to the water bath.Once it exceeds 80° C, remove the test tube from the water bath but maintain the thermometer position in proportion to the mixture.Add water to the beaker so that the solid is well below the level of the water.The thermometer should maintain position in proportion to the BHT, but the test tube should be out of the water bath beaker.Heat the water bath to about 90° Celsius.
516 words (1.3 pages)
c Half fill the 250 cm3 beaker with cold water.After a time lag, the water begins to steam and clouds of purple iodine vapour are given off, indicating that an exothermic reaction has started.Apparatus and chemicals Eye protection Thick chemically-resistant gloves such as marigold industrial blue nitrile Access to a fume cupboard The teacher will require: Mortar and pestle Heat resistant mat, 30 x 30 cm Watch glasses, about 10 cm diameter, 2 Reduction tube (see note 1) Test-tubes, 3 Test-tube rack Teat pipette Filter paper Spatula or wooden splint Bosses, clamps and stands Chemicals for one demonstration: Aluminium foil, a few cm2 Aluminium powder (Highly flammable, Contact with water may liberate hydrogen), 0.The protective oxide layer ...
3314 words (8.3 pages)
One could say that an electric hot water heater is an electric boiler although there are electric boilers that can heat water to steam temperatures.Water Tube Boiler sizes range from from 10 million BTU/h boilers all way up to 300 million BTU/h and these boilers are generally found in medium to large commercial/industrial use and can be either steam or hot water boiler in low to high pressure boiler applications.They have different designs and piping configurations as a steam boiler system is designed to turned the water into steam and uses gravity and pressure to deliver the heat and the hot water boiler systems are designed to simply make hot water to be circulated (by a circulator or pump) through a piping system to provide heat.Conde...
4791 words (12.0 pages)
Though the procedure called for 5mL of water to be added, the product already contained a large amount of moisture and the drying process available would likely not be able to remove the moisture completely.At the completion of the 20 minutes, the hot plate was turned off, and the Erlenmeyer flask was removed from the heated water and the 2mL de-ionized water was added.To prepare the heating mechanism for the experiment, 250mL of tap water was poured into a 400mL beaker, and this water was then heated on a hot plate to 85⁰C.Once the product finished cooling to 45⁰C in the Erlenmeyer flask, this was then added to the water in the beaker.First, 2 medium-sized test tubes were obtained from the front of the laboratory, cleaned using the basi...
2104 words (5.3 pages)
The cooling has the purpose to remove the humidity from the air, up to a saturation humidity of 2 degree Celsius & also to convey low temperature air to the dehumidifying tower, thus favoring the water absorption in the silica gel.Some silica gel indicator is placed near the sight glasses, changing its color accordingto the quantity of absorbed water; thus saturating with water, it changes blue to pink.•Distilled water .•Distilled water .The residual unconverted SO2 is absorbed in the scrubbing column in which a water and caustic soda solution is continuously recycled.
4503 words (11.3 pages)
The solution was transferred to twenty milliliters of cold, deionized water which resulted in the precipitation of a white substance—Aspirin after six minutes of cooling.The specimen was returned to a test tube with deionized water and placed in a boiling water bath.Once the vacuum crudely dried the powder, the filter paper and contents of the Buchner Funnel where placed on a paper towel to further removal of water while the aqueous layer within the filter flash was discarded in the liquid waste container.Once the powder was no longer visible, the test tube was transferred to an ice water bath where the crystals reformed.After nineteen minutes, the test tube was removed.
780 words (2.0 pages)
Mixture was filtered and rinsed with cold ethanol, then cold water, then took the crude weight of the product.The mixture was filtered and rinsed with cold ethanol and cold water, recrystallized with methanol, filtered, dried and weighted to get final product.Tetraphenylcyclopentadienone(0.500g), glyme(3mL), and a boiling chip was added to a reaction tube.The solid was vacuum filtered, washed two times with cold water, then two times with cold ethanol.The reaction tube was cooled again and had toluene(2mL) added then placed in ice.
557 words (1.4 pages)
This is usually helpful in determining the freezing point, provided the super cooling is not too pronounced.The eutectic composition is that at which two solids crystallize out in a ratio equal to that of the melt, and the cooling curve obtained would have the same characteristics as that of a pure substance.Super cooling often occurs in this system.600 ml beaker filled of tap water and 2 or 3 boiling chips .Stand the test tube in a beaker of cool tap water to speed the cooling.
1561 words (3.9 pages)
Caution: Be sure tube is cool before handling it.Examine residue and test its solubility in water.Transfer sodium hydrogen carbonate sample to test tube.Touch tube at bottom with hand and record observation.The mass of the test tube and its contents will be determined and recorded.
402 words (1.0 pages)
The test tube was then disposed of properly.Once the supernatant was discarded, 3mL of DI H2O were added to the test tube using a sterile pipette and centrifuged for 2 minutes.The mass of each piece of laboratory equipment (test tube & rack) used in this experiment was calculated prior to the addition of any substance or solution.The test tube with the remaining contents was allowed to cool to room temperature then weighed using an analytical balance.Using a clean sterile pipette, 2mL of 1.00 M KI solution was transferred to a clean dry test tube and weighed using an analytical balance.
788 words (2.0 pages)
After warming for 1 minute the solution was allowed to cool to room temperature, and then placed in ice-cold water.Then the boiling tube was warmed in the water bath until a yellow solution was obtained.The tube was then placed in the water bath and heated on the steam bath until the mixture was completely dissolved.Then 1 mL concentrated ammonia and 30 mL water were added to the conical flask.It was ensured that the rubber tubing was disconnected first and then the water aspirator turned off, so as to prevent sucking back and so contamination of the substance.
2766 words (6.9 pages)
4) Put thermometers into both test tube.Every minute the coffee was getting cooler (milk was getting warmer until the room temperature), but when we added the milk into coffee it started to cool more faster.Controlled: To control variables we can change hot coffee/water and milk every minute, or put hot coffee/ water into thermos and milk into object that has same temperature.2) In the first test tube pour milk .We used only one metal rod, after hot water we put it into milk ( the rod was hot) and maybe it made a effect to results.
1616 words (4.0 pages)
The water bath was replaced with ice and tap water and the reaction solution stirred intermittently with a glass stir rod for ~ 10 minutes to complete the crystallization of the product.The flask was removed from the water bath after all the cholesterol was completely dissolved and allowed to cool to room temperature.The two layers formed were then separated as water layers and organic (ether) layers.About 30 mg of the commercial cholesterol starting material was added to tube A; ~30 mg of dibromocholesterol to tube B; ~30 mg of the synthesized cholesterol product to tube C; ~0.3 mL of 1-chlorobutane to tube D; and ~ 0.3 mL of t-butyl chloride to tube E. In addition, about 3 mL of acetone was added to each tube to completely dissolve al...
1890 words (4.7 pages)
Let the tube cool, and try to dissolve the residue in a few cm3 of water, warming if necessary.The color change in this compound shows that by adding water to the anhydrous residue, that the same bonds that were broken my dehydrating the compound where reformed when adding water.For example, Sucrose, when heated, water residue appeared on the test tube, and was soluble in water, but the compound didn’t show reversibility.Only one compound turned about to be efflorescent, which means that it lost water, which was Sodium Carbonate.This percent was found by using the formula below: % water in hydrate=(mass of water in hydrate/mass of the entire hydrate) .
1064 words (2.7 pages)
For example, if there was a mixture that has water and two solids (one of them being acetamide), we can just boil the mixture and let it reach approximately over 81 degrees Celsius, we would know that the acetamide melted into a liquid and we can filter out the solid that is left.When the alcohol starts to boil I extinguish the burner and wait until the last bubble emerges from the test tube and recorded the temperature.C. What would be the effect of increasing the amount of crystals in the capillary tube?After that I made a water bath with a beaker and put in the test tube with the thermometer.I then used a burner and a burner stand to heat up the water bath.
482 words (1.2 pages)
10 mg of commercial cholesterol was placed in tube 1, ~10mg of the dibromocholesterol to tube 2 ~10 mg of your synthesized cholesterol to tube 3, ~10 mg of 2-chlorobutane to tube 4, and 10 mg of cyclohexene to tube 5.The flask was placed in a warm water bath and then ice cooled for 10 minutes until all but 5 mL of the ether remained following a precipitate formation from the solution.About 30 mg of the commercial cholesterol starting material was added to tube A; ~30 mg of dibromocholesterol to tube B; ~30 mg of the synthesized cholesterol product to tube C; ~0.3 mL of 1-chlorobutane to tube D; and ~ 0.3 mL of t-butyl chloride to tube E. In addition, about 3 mL of acetone was added to each tube to completely dissolve all the compounds.T...
2225 words (5.6 pages)
The cylinder is provided with separate openings for exhaust gas and cooling water.Zeolite Zeolite also forms a pair with water.Zeolite – Water, with a desorption temperature of 250˚C, was eliminated.Considering these points, we selected silica gel – water to be the pair for our prototype.One hydroxyl can adsorb one molecule of water.
3277 words (8.2 pages)
A body in water loses heat at a more rapid rate than a body of the same temperature kept in air because water is a better conductor of heat than air.Evaporation of water (for instance in perspiration) from the body surface speeds up the rate of cooling.* Another test tube was filed with hot water and placed on a test-tube stand.Evaporation of water (for example in sweat) from the body surface speeds up the rate of cooling.* Start the stopwatch and record the temperature of the water in the test tube at regular intervals of 1 minute.
1413 words (3.5 pages)
Because steel is subject to corrosion in the presence of even low concentrations of oxygen, water must be practically 100 percent oxygen free.Many of the waste heat recovery technologies used in building co/trigeneration systems require hot water, some at moderate pressures of 15 to 150 psig.Small to Medium Air-Cooled Commercial Chillers – All existing commercial chillers, whether using waste heat, steam or natural gas, are water-cooled (i.e., they must be connected to cooling towers which evaporate water into the atmosphere to aid in cooling).The hot water or steam is then used to provide hot water or steam heating and/or to operate thermally activated equipment, such as an absorption chiller for cooling or a desiccant dehumidifer for d...
1379 words (3.4 pages)
Fill graduated cylinder with water .b. Plug hot water tub in .h. Place cylinder in hot water tub until temperature reaches 44C .d. Place Water tub on table .This slightly adjusts the liver to water ratio of the liver solution but it does not throw off the collection of data because it applied to all three levels of the Independent variable ensuring precision.
2334 words (5.8 pages)
Hypothesis: It is expected that when the bromeline enzyme isn’t present, that the gelatin will remain staying as gel, when dissolved in water.They were named like following; #1: 2,5 ml tap water .Two pieces of gelatin were cut into smaller pieces and thereafter heated in approximately 100 ml of water in a beaker using a Buntson burner.When all the gelatin was dissolved, the heat was turned off and the solution got time to cool down, approximately 5-10 minutes.Conclusion: When doing the investigation of the effect of the enzyme Bromeline has on gelatins ability to solidify, it was observed that only the untreated raw pineapple juice was able to break down the proteins in the gelatin.
467 words (1.2 pages)
The test tube was immersed in the water bath for 5 minutes.1ml of casein, tyrosine, albumin and glycine was placed into separate labeled test tube.3 drops of millon reagent was added to the test tube.The test tube was let cooled.The test can be done.
793 words (2.0 pages)
Overall the polystyrene foaming did trap heat in the air pockets, meaning that the water did lose heat slower than the un-insulated one did.Lastly I can change the amount of time I heat the water up for and how long I leave into “cool”.To keep it a fair test, we will need to put 40ml of water into each boiling tube and make sure they are all the same starting temperature 100’C (boiling point) then turn of the Bunsen burner and let there cooling down times the same and each boiling tube is well insulated properly.In my investigation the things I can change, which are the dependent variables is the volume of water used because this will depend on how fast the water will heat up and lose heat.I heat up some water in a beaker using a Bunsen ...
2135 words (5.3 pages)