Excess molar volumes were measured at 308.15K as a function of composition by a direct dilatometer method for binary liquid mixtures of 4-methylpentan-2-ol + n-hexane, + n-heptane, + n-octane, + n-decane and + n-dodecane. All the mixtures exhibit positive excess volumes over the whole mole fraction range. VE results of 4-Methylpentan-2-ol with n-alkanes were compared with VE of Hexanol-1 + n-alkanes. The variation of VE with the change in the position of either alkyl group or –OH group is discussed. 1. Introduction The molar excess volumes of binary liquid mixtures particularly alkanol – alkanes mixtures have been determined by many workers (Kaur et al.,1989, 1991and Mahajan et al.,2013) and the results have been utilized to check the validity …show more content…
Kaur,1985) which give sigmoid shape with (n-hexane, n-heptane and n-decane), i.e. show both negative and positive values at low and high mole fraction range. This can be explained as consequence of two opposing effects, the disruption of H-bonded alcohol aggregates by alkane molecules contribute negative VE whereas change in free volume and interstitial accommodation of smaller alkane molecules into the alkanol structure give negative contribution. The latter effect gets stoically hindered in 4-methylpentan-2-ol due to positive contribution due and is dominated by the positive contribute due to disruption of H-bonds. Self association due to H-bonds also become weaker due to steric hindrance to H-bond formation in 4-methylpentan-2-ol as compared to Hexan-1-ol which cause more positive VE values for 4-methylpentan-2-ol. The shape of the molecule is another factor which contributes more positive value of VE to 4-methylpentan-2-ol. The Hexan-1-ol molecule is planer and elongated in same fashion as those of n-alkanes. The alignment of these molecules on mixing is ordered due to Vander Waal’s forces. The 4- methylpentan-2-ol molecules are bulky and spherical in shape. The alignment on mixing is likely to be random. These molecules may also destroy the ordered alignment of n-alkane
Cadet Eric Wiggins Date: 18 September 2014 Course Name: Chem 100 Instructor: Captain Zuniga Section: M3A Identification of a Copper Mineral Intro Minerals are elements or compounds that are created in the Earth by geological processes. The method of isolating metals in a compound mineral is normally conducted through two processes.
Next, about 10 mL of both solutions, Red 40 and Blue 1, were added to a small beaker. The concentration of the stock solution were recorded, 52.1 ppm for Red 40 and 16.6 ppm for Blue 1. Then, using the volumetric pipette, 5 mL of each solution was transferred into a 10 mL volumetric flask, labelled either R1 or B1. Deionized water was added into the flask using a pipette until the solution level reached a line which indicated 10 mL. A cap for the flask was inserted and the flask was invented a few times to completely mix the solution. Then, the volumetric pipette was rinsed with fresh deionized water and
Feras Kaid Chem 2415-43 TA: Rio Assessment 1 Conclusion In this lab, there were 4 different distillations that were performed each with the same end goal to separate the two different organic compounds, cyclohexane and toluene. We used the boiling points of the two compounds to separate them using the following 4 techniques: microscale simple distillation, miniscale simple distillation, miniscale fractional packed distillation, and miniscale fractional unpacked distillation. The three different miniscale distillations were used to predict the accuracy of the distillation by comparing them to one other. The most accurate of the three distillations is the miniscale fractional packed distillation because this type uses a Vigreux column instead
First, the 250-mL graduated cylinder, 100-mL graduated cylinder, and the 10-mL graduated cylinder were observed to see the volume of the liquid in each one. Then, one digit further was estimated, and the results were recorded. After that, the 25-mL graduated cylinder and the 50-mL beaker were cleaned and dried. Next, their masses were measured on the scale, and the results were rounded to the nearest thousands decimal place. Subsequently, the Erlenmeyer flask was filled with 100 mL of distilled water.
The lab started off by measuring critical materials for the lab: the mass of an an empty 100 mL beaker, mass of beaker and copper chloride together(52.30 g), and the mass of three iron nails(2.73 g). The goal of this experiment is to determine the number of moles of copper and iron that would be produced in the reaction of iron and copper(II) chloride, the ratio of moles of iron to moles of copper, and the percent yield of copper produced. 2.00 grams of copper(II) chloride was added in the beaker to mix with 15 mL of distilled water. Then, three dry nails are placed in the copper(II) chloride solution for approximately 25 minutes. The three nails have to be scraped clean by sandpaper to make the surface of the nail shiny; if the nails are not clean, then some unknown substances might accidentally mix into the reaction and cause variations of the result.
Introduction The purpose of this lab was to compare simple distillations of two sets of liquids by graphing the boiling points. One set of simple distillation of two liquids were supposed to have a boiling point difference of bout 30C while the other set of simple distillations had a melting point difference of about 57C. Furthermore, by conducting this experiment, students would develop a better understand of distillation and gas chromatography. Furthermore, I hypothesized that cyclohexane and p-xylene distill better than cyclohexane and toluene since cyclohexane and p-xylene have a larger boiling point difference than cyclohexane and toluene. The boiling point of cyclohexane is 80.74C while the boiling point for p-xylene is 138.23C and the boiling point for toluene is 110.6, thus
The theoretical molar mass of butane was found by adding the molar mass of each element that makes up butane. This means that the molar mass of carbon was multiplied by four and added to the molar mass of hydrogen multiplied by ten, yielding a molar mass of 58.124g/mol. The calculated molar mass of butane was found by using the equation, M = (DRT)/P, where the density was found by dividing the mass of butane collected by the volume of butane in the graduated cylinder in liters and the pressure was the partial pressure in kilopascals of butane. After finding these two values, they were subtracted, divided by the theoretical molar mass of butane, and finally multiplied by
Lone Pairs ADI Lone pairs, the electrons that the central atom does not share during a covalent bond, can and will affect the shape of a molecule in various ways. During this lab, the goal was to answer the guiding question of, “How does the number of lone pairs affect the shape of the molecule?” Answering this question served to cement in those participating in the lab an understanding of the affect a central atom’s number of lone pairs will have on the shape of the molecule, and be able to identify a pattern of molecular shapes and their central atom’s lone pairs. We conducted this lab by first experimenting with 3-D molecular structures on a website, becoming familiar with the geometry of molecules and what exactly lone pairs were.
The specific purpose of this experiment is to determine the composition of vapor and liquid phases for different mixtures of a pair of volatile liquids using refractive values and distillation techniques involving the construction of two different types of phase diagrams. Moreover, these different phase diagram might be analyzed and compared individually in order to have a better understanding about the multiple types of phase equilibrium and phase change that occurs. For the procedure, the two components are benzoic acid and o-toluic acid. The first step of this experiment is to accomplish the part A: run samples A1 to A5 and B1 to B5. For this step, place a beaker of silicon oil on top of a hot plate until the temperature reaches 135 +/-
Introduction A way to determine the molar mass of an unknown substance is to use other properties of that substance and solve for desired information. In this experiment, a colligative property, like the freezing point of an aqueous solution of the unknown substance, was used to find the molar mass of the substance. With the molar mass discovered, the identity of the substance was found. Material and Methods First, a Vernier temperature probe was attached to a plastic rod using rubber bands.
Cyclohexane was collected from 26 ml to 35 ml, thus 9 ml of cyclohexane was collected. Therefore the observed ratio of DCM to cyclohexane was 18:9 or 2:1. Two sources of error may have affected the experiment. Firstly, the experiment required volumes of liquid to be recorded while the vapours were distilling.
The crude oil is heated in a tall cylinder called fractionator for at least 350 degC. The process is based on the principle that different substances boil at different temperature. The cyclohexane content of naphtha fraction of crude oil can vary from 0.5 to 5.0 volume %. N-hexane, isohexanes, methyl cyclopentane, benzene and dimethyl pentanes have normal boiling points very close to cyclohexane.1 Advantages: 1. Uses a simple method of cyclohexane recovery. Disadvantages: 1.
Properties of Substances Express Lab 1)The purpose of this lab was to compare the physical properties of different types of solids and how the properties of solids are determined by their intermolecular forces and their intramolecular bonds. Then we were to classify each type of solid as either ionic, metallic, non-polar molecular, polar molecular, or network. Paraffin wax classified as a non-polar molecular, Silicon dioxide was classifies as a network, Sodium chloride was classified as ionic, Sucrose was classified as polar molecular and Tin was classified as metallic. (2)The intermolecular forces that are present in Paraffin wax are dispersion forces, because it is non-polar and carries a negative charge. Followed by Sucrose that has
Properties of Ionic and Covalent Substances Lab Report Introduction The purpose of this lab was to determine which of the following substances: wax, sugar, and salt, are an ionic compound and which are a covalent compound. In order to accurately digest the experiments results, research of definitions of each relating led to the following information: ionic compounds are positive and negatively charged ions that experience attraction to each other and pull together in a cluster of ionic bonds; they are the strongest compound, are separated in high temperatures, and can be separated by polar water molecules. A covalent compound forms when two or more nonmetal atoms share valence electrons; covalent compounds are also
DETERMINATION OF PERCENTAGE ETHANOL IN BEVERAGES 1. Introduction to Gas Chromatography Gas chromatography is a very powerful separation technique for compounds that are reasonably volatile. The components of a sample partitions into two phases, the 1st of these phases is a immobile bed with a great surface area, and the other is a gas phase that permeates through the immobile bed. The sample is evaporated and passed by the mobile gas phase or the carrier gas through the column. Samples separates into the stationary liquid phase, based on their solubilities at the given temperature.