To Determination the Partition Coefficient of Ethanoic Acid Between Water and Butan-2-Ol Essay Example

To Determination the Partition Coefficient of Ethanoic Acid Between Water and Butan-2-Ol Paper To determination the partition coefficient of ethanoic acid between water and butan-2-ol. Procedure 1. The room temperature was recorded. 2. 15cm3 of the given aqueous ethanoic acid and 15cm3 of butan-2-ol were poured into a 100cm3 separating funnel, using suitable apparatus. The funnel was stoppered and was shook vigorously for 1 to 2 minutes. (The pressure in the funnel was released by occasionally opening the tap. ) 3. 10cm3 of each layer was separated approximately. (The fraction near the junction of the two layers was discarded. ) 4. 10. cm3 of the aqueous layer was pipetted into a conical flask and was titrated with 0. 1 M sodium hydroxide solution using phenolphthalein. 5. Using another pipette, 10. 0 cm3 of the alcohol layer was delivered into a conical flask and was titrated with 0. 1 M sodium hydroxide solution. 6. Steps (2) to (5) was repeated with another separating funnel using the following volume: 25cm3 of aqueous ethanoic acid and 15cm3 of butan-2-ol 7. For each exper iment, the ratio of the concentration of ethanoic acid in the aqueous layer to that in the butan-2-ol layer was calculated. Result Room temperature: 29? Volume of butan-2-ol: 15 cm3 |Volume of 0. 2M ethanoic acid / |Volume of 0. 1M NaOH titre for |Volume of 0. 1M NaOH titre for|Partition coefficient | |cm3 |aqueous layer / cm3 |alcohol layer / cm3 |K= | |15 |10. 00 |12. 55 |0. 796 | |25 |12. 10 |15. 60 |0. 76 | Conclusion The partition coefficient of ethanoic acid between water and butan-2-ol is : = =0. 786 Discussion 1. Shaking is necessary in step (2) because it made it faster to attain equilibrium state. 2. When temperature increases, the solubility of the two solvents increase. But the rate of the increase in solubility are not the same, it is expected that the partition coefficient varies with temperature. 3. The aim of titration is to find the concentration of the solvent, but not the total number of mole in the solvent. We will write a custom essay sample on To Determination the Partition Coefficient of Ethanoic Acid Between Water and Butan-2-Ol specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on To Determination the Partition Coefficient of Ethanoic Acid Between Water and Butan-2-Ol specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on To Determination the Partition Coefficient of Ethanoic Acid Between Water and Butan-2-Ol specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Therefore, the volumes of the aqueous and alcohol solution used in the titration must be known as accurately as possible in order to find accurately concentration. The aim of adding aqueous ethanoic acid and 2-methypropan-1-ol is only to leave the mixture to equilibrium and provide enough solvent for the titration. Therefore the amounts of aqueous ethanoic acid and 2-methypropan-1-ol need not be measured out accurately. 4. The following assumptions are made: a) The temperature of the mixture remained constant throughout the experiment. This assumption was valid as it was felt (by hand) that the temperature of the separating funnel did not changed throughout the experiment. b) Ethanoic acid, water and butan-2-ol are non-volatile and do not evaporate slowly. This assumption is not valid because there is a smell of alcohol over the separating funnel. That means that there are particles coming out from the mixture in the separating funnel. 5. Solvent extraction is more efficient if the extraction solvent is added in small portions several times instead of all at once. Therefore it is more fficient to extract a solute with two 25cm3 portions of solvent rather than with a single 50cm3 extraction. 6. The applications of the partition law: a) By partition law, the KD can be found experimentally. The amount of the solute that can be extracted using solvent extraction can be predicted, instead of using other complex method. b) By partition law, we know that the amount of solute extracted is more when the extracting solvent is added in several small portions instead of all at once. 7. Butan-2-ol is much lighter than water. Therefore butan-2-ol is at the top of the mixture while water is at the bottom.

A Beginners Guide to Statistics

A Beginners Guide to Statistics How many calories did each of us eat for breakfast? How far from home did everyone travel today? How big is the place that we call home? How many other people call it home? To make sense of all of this information, certain tools and ways of thinking are necessary. The mathematical science called statistics is what helps us to deal with this information overload. Statistics is the study of numerical information, called data. Statisticians acquire, organize, and analyze data. Each part of this process is also scrutinized. The techniques of statistics are applied to a multitude of other areas of knowledge. Below is an introduction to some of the main topics throughout statistics. Populations and Samples One of the recurring themes of statistics is that we are able to say something about a large group based on the study of a relatively small portion of that group. The group as a whole is known as the population. The portion of the group that we study is the sample. As an example of this, suppose we wanted to know the average height of people living in the United States. We could try to measure over 300 million people, but this would be infeasible. It would be a logistical nightmare conduct the measurements in such a way that no one was missed and no one was counted twice. Due to the impossible nature of measuring everyone in the United States, we could instead use statistics. Rather than finding the heights of everyone in the population, we take a statistical sample of a few thousand. If we have sampled the population correctly, then the average height of the sample will be very close to the average height of the population. Acquiring Data To draw good conclusions, we need good data to work with. The way that we sample a population to obtain this data should always be scrutinized. Which kind of sample we use depends on what question we’re asking about the population. The most commonly used samples are: Simple RandomStratifiedClustered It’s equally important to know how the measurement of the sample is conducted. To go back to the above example, how do we acquire the heights of those in our sample? Do we let people report their own height on a questionnaire?Do several researchers throughout the country measure different people and report their results?Does a single researcher measure everyone in the sample with the same tape measure? Each of these ways of obtaining the data has its advantages and drawbacks. Anyone using the data from this study would want to know how it was obtained. Organizing the Data Sometimes there is a multitude of data, and we can literally get lost in all of the details. It’s hard to see the forest for the trees. That’s why it’s important to keep our data well organized. Careful organization and graphical displays of the data help us to spot patterns and trends before we actually do any calculations. Since the way that we graphically present our data depends upon a variety of factors. Common graphs are: Pie charts or circle graphsBar or pareto graphsScatterplotsTime plotsStem and leaf plotsBox and whisker graphs In addition to these well-known graphs, there are others that are used in specialized situations. Descriptive Statistics One way to analyze data is called descriptive statistics. Here the goal is to calculate quantities that describe our data. Numbers called the mean, median and mode are all used to indicate the average or center of the data. The range and standard deviation are used to say how spread out the data is. More complicated techniques, such as correlation and regression describe data that is paired. Inferential Statistics When we begin with a sample and then try to infer something about the population, we are using inferential statistics. In working with this area of statistics, the topic of hypothesis testing arises. Here we see the scientific nature of the subject of statistics, as we state a hypothesis, then use statistical tools with our sample to determine the likelihood that we need to reject the hypothesis or not. This explanation is really just scratching the surface of this very useful part of statistics. Applications of Statistics It is no exaggeration to say that the tools of statistics are used by nearly every field of scientific research. Here are a few areas that rely heavily on statistics: PsychologyEconomicsMedicineAdvertisingDemography The Foundations of Statistics Although some think of statistics as a branch of mathematics, it is better to think of it as a discipline that is founded upon mathematics. Specifically, statistics is built up from the field of mathematics known as probability. Probability gives us a way to determine how likely an event is to occur. It also gives us a way to talk about randomness. This is key to statistics because the typical sample needs to be randomly selected from the population. Probability was first studied in the 1700s by mathematicians such as Pascal and Fermat. The 1700s also marked the beginning of statistics. Statistics continued to grow from its probability roots and really took off in the 1800s. Today, it’s theoretical scope continues to be enlarged in what is known as mathematical statistics.