Wait a second!
More handpicked essays just for you.
More handpicked essays just for you.
Temperature effect on air pressure
Gas chromatography research
Gas chromatography research
Don’t take our word for it - see why 10 million students trust us with their essay needs.
Recommended: Temperature effect on air pressure
1. Is cyclohexane polar or nonpolar? (0.5 pt)
Cyclohexane is non polar giving its symmetry and that it is made of simply carbon and hydrogen.
2. Is toluene polar or nonpolar? (0.5 pt)
Toluene is non polar given it equal electron distribution in a covalent bond.
3. Would you expect cyclohexane and toluene to form a homogeneous or heterogeneous solution? (0.5 pt)
Given that cyclohexane and toluene are non-polar compounds, they will be miscible compounds to each other and they will form a homogeneous solution
4. What is the boiling point of toluene and cyclohexane? (1 pt)
The boiling point for toluene is 110.6oC, and for cyclohexane is 80.7oC .
5. Define vapor pressure. (1 pt)
Vapor pressure is the pressure of a gas above its liquid.
…show more content…
What are azeotropes? (1 pt)
Azeotropes are mixture that do not follow Raoult's law and that distills at a constant boiling point and with a constant composition.
7. Does toluene or cyclohexane have a higher vapor pressure? Explain your reasoning. Use the relationship between vapor pressure and boiling point to explain your answer. (2 pts)
Cyclohexane have a higher vapor pressure since it has a low melting point. The vapor will enrich in the lower boiling-cyclohexane. Cyclohexane will evaporate first than toluene and more gas particle of cyclohexane will remain above the liquid, which is going to contribute more to the vapor pressure of the solution.
8. What is distillation and what is it used for? (2 pts)
Distillation is general technique used for removing a solvent, purifying a liquid, or separating the components of a liquid
…show more content…
How is distillation used in the oil industry? (2 pts)
Usually, fractional distillation is used in the oil industry to take advantage of all the products that can be extracted from a crude oil. In a column distillation, at different temperature, we can obtain various compounds that we use in our daily life, such as gases(butane), petroleum (cars), naphtha (chemicals), kerosene (jet fuel), diesel (trucks), fuel oil (power station), and residue (roads, and bitumen). 11. What is a gas chromatography used for? How does it work? (2 pts)
A gas chromatography (GC) is used for a quantitative analysis to separate mixtures with low melting point. Essentially a gas chromatography analysis use a thermal conductivity (TC) detector that will produce an electronic signal whose voltage is proportional to the amount of each component. Each component will reach the detector at different time. The components separate according to the polarity and volatility. Some components will move faster than others. The GC will print out a graph which plots the changes in voltage as a function of time.
12. Why should we heat the solution slowly? (0.5 pts)
The solution should heated slowly to ensure an optimal thermal
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
The boiling point of the product was conducted with the silicone oil. Lastly, for each chemical test, three test tubes were prepared with 2-methylcyclohexanol, the product, and 1-decene in each test tube, and a drop of the reagent were added to test tubes. The percent yield was calculated to be 74.8% with 12.6g of the product obtained. This result showed that most of 2-methylcyclohexanol was successfully dehydrated and produced the product. The loss of the product could be due to the incomplete reaction or distillation and through washing and extraction of the product. The boiling point range resulted as 112oC to 118oC. This boiling point range revealed that it is acceptable because the literature boiling point range included possible products, which are 1-methylcyclohexene, 3-methylcyclohexene, and methylenecyclohexane, are 110 to 111oC, 104oC, and 102 to 103 oC. For the results of IR spectroscopy, 2-methylcyclocahnol showed peaks at 3300 cm-1 and 2930 cm-1, which indicated the presence of alcohol and alkane functional group. Then, the peak from the product showed the same peak at 2930 cm-1 but the absence of the other peak, which indicated the absence of the alcohol
It was learned that changing the volume of the same substance will never change the boiling point of the substance. However having two different substances with the same volume will result in two different boiling points. The purpose of this lab was to determine if changing the volume of a substance will change the boiling point. This is useful to know in real life because if someone wanted to boil water to make pasta and did not know how much water to
Carbon Dioxide must be under a pressure of at least 415.8 kPaA For it to turn into liquid form. Oxygen and Nitrogen are very similar to this.
Aspirin is 3.3 g/L soluble in water (3). Aspirin can be soluble in ethanol, DMSO, or water (2). Aspirin has polar groups that when put with polar water molecules can form hydrogen bonds. Aspirin is an asymmetrical molecule. When drawing the Lewis Dot Structure, a person can see that the bonds are polar. There are also dipole moments making the molecule polar. Dipole molecules are composed of a higher electronegative atom pulling electrons towards it (11). It is more soluble in basic solutions than water and acidic solutions (4). The Lewis Structure also reveals that there are many double bonds between the carbons and two double bonds between oxygen and carbon.
Since, the expected weight was 50.63 mg the percent yield is 59.3%. A TLC was conducted on this final product and a faint spot of 4-tert-butylcyclohexanone still appeared in lane 3 of the plate; meaning the reaction did not fully go to completion. The Rf values were 0.444, 0.156, and 0.111, where the lowest value is the trans isomer and the highest value is the ketone. This affected the IR spectrum conducted by having a carbonyl group peak at 1715 cm-1 which should not be present if all the product was 4-tert-butylcyclohexanol. However, the IR spectrum still showed peaks at 3292 cm-1 (hydroxyl group), 2939 cm-1 (sp2 carbon bonded to hydrogen) and 2859 cm-1 (sp3 carbon bonded to hydrogen) which support the presence of the alcohol. The accepted melting point of 4-tert-butylcyclohexanol is in the range of 62 – 70˙C (Lab Manual). The two melting point measurements using the Mel-Temp® machine gave ranges of 57 – 61˙C and 58 – 62˙C, which is not exact due to some 4-tert-butylcyclohexanone being present that has a low melting point of around 47 – 50˙C
A mixture, according to definition, is a combination of components and substances mixed together to form one particular substance, uniform or not. Mixtures can be classified down to two types, homogeneous and heterogeneous. Homogeneous mixtures are generally uniform, or have the same consistent composition throughout, whereas heterogeneous mixtures are not entirely defined and vary in
Alcohol particles break their bonds when they mix with oxygen. This is known as an exothermic reaction. Boiling points will be increased because energy is needed, bonds can be formed and broken. Breaking bonds need less energy than is needed to form bonds - an exothermic reaction. Bigger molecules use high energy to break down.
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
...lt in water. Although water is generally considered to boil at 100°C (212°F), water actually boils when the vapor pressure is the same as the air pressure around the water (Physics, 2006). Because of this the boiling point of water is lower in lower pressure and higher at higher pressure. Did you know that baking cookies above 3500 feet above sea level require special cooking directons (Burt, 2004).
1-Butanol with intermediate polarity was soluble in both highly polar water and non polar hexane as 1-butanol can be either polar or non polar compound. 1-Butanol was polar based on the general rule of thumb stated that each polar group will allow up to 4 carbons to be soluble in water. Also, 1-butanol can be non polar due to their carbon chains, which are attracted to the non polarity of the hexane.
5. In a gas increasing the pressure means molecules are more squashed up together, so there will be more collisions. My Investigation. I am going to investigate the concentration variable. I have chosen this because in my opinion it will be the easiest one to measure.
Therefore, the relationship between pressure drop and boil-up rate means that more volume of vapour educed per unit time results in more restriction of the holes in the sieve tray and that caused by passing of vapour through the liquid on top of the tray. Hence, the higher the velocity, the higher the boil-up rate and so does the overall pressure drop.
Third, the liquid will enter to the expansion valve with the higher pressure and leaves with the low pressure.
When the liquid level in both arms is the same, the pressure of the sample of gas inside the closed end must equal the pressure of the external atmosphere since the downward force on the two columns of liquid is then equal. When the liquid levels are unequal, the pressures must differ. The difference in pressure can be measured in units of length of the vertical column of liquid. The mm Hg, or its modern version the torr, originated in this use of the manometer. Mercury is particularly convenient for use in manometers (and barometers) because at room temperature it has low vapor pressure, does not wet glass, and has a high density. Other liquids such as linseed oil or water have also been used in manometers.