ipl-logo

Salicylic Acid Investigation

1308 Words6 Pages

1. Aims
a) To find the molar absorptivity of salicylic acid by plotting a graph of absorbance against the concentration of salicylic acid, using the standard solution.
b) To find the concentration of aspirin at the various time intervals using the molar absorptivity value in the previous part, initial concentration of aspirin and the concentration of salicylic acid obtained from the decomposition of the aspirin pill.
c) Lastly, to calculate the rate constant of the decomposition of aspirin by plotting a graph of ln[aspirin] against time and making use of the gradient of the best fitted line along with the standard deviation.
2.Data Treatment and Analysis

In order to find the molar absorptivity of salicylic acid, a UV spectroscopy is carried …show more content…

Iron(III) solution was added to the salicylic acid to form a organometallic complex. This makes use of the reaction between the phenol functional group in salicylic acid and ferric ions which allows for visibility due to its violet hue(1). The absorbance is directly proportional to the concentration of salicylic acids. This means that the higher the concentration of salicylic acid, the higher the amount of salicylate-iron complex formed, resulting in higher violet intensities and hence a higher absorbance, as seen from table 1. Since the Fe3+ ions react with the singular phenol functional group in salicylic acid, the amount of Fe3+ added should be in a 1:1 ratio with the concentration of salicylic acid.
Fig 2. Plot of concentration of standard salicylic acid against …show more content…

This is only possible because aspirin decomposes to salicylic acid in a 1:1 ratio. ln[aspirin] was also calculated so that the plot obtained will show a linear relationship with time and allows us to analyse trends between the two variables.
Although the data is a little sporadic, there is a visible trend of a gradual increase of salicylic acid concentrations and a decrease in aspirin concentrations.
Fig 4. Plot of ln[Aspirin] against time The plot in Fig. 4 shows a strong linear relationship between ln[aspirin] and time. The calculated r2 value is 0.99236 while the gradient is -6.94931 x 10-5. The standard deviation of the regression line is as small as 2.73×10-6, as expected from the properties of ln values. The gradient, which is essentially the change in concentration divided by the change in time, follows the differential rate law for first order reactions where:
Rate = (-d[aspirin])/dt=

Show More
Related
1410 Words | 6 Pages

Note the gradient of the line Exit the linear regression dialog and store the latest run data Add 2, 3, 4 drops of enzyme catalase solution to test tube 2, 3, 4 respectively and repeat the above procedure for each test tube. Access other groups results and fill table 4 RESULTS In this experiment it was found that increase in number of drops of enzyme suspension led to increased pressure as shown in the table 3.

Read More
704 Words | 3 Pages

Pure ASA crystals are isolated from the solution with a Hirsch Funnel that was used with a filter. The melting point of the pure ASA crystals were calculated in order to calculate of absorbance. Iron (III) salicylate dianion must contain the acidified solution Fe3+ in order to measure the absorbance values. The level of the impurity can

Read More
886 Words | 4 Pages

To graph population or disease, we needed to use exponents; in equation-form, the exponent was an X, but it could be substituted for any number, which would represent the year. You would also find the current population or number of cases and divide them by the amount the previous year (the starting number) and add that to one to find the rate, which would show you if it was growth or decay. Finally, you use the starting number as your constant or y-intercept. If you were trying to graph the decay of a population, the equation could be: y=150,000(1.5)x; if you were trying to graph decay, the equation could be: y=150,000(0.5)x. You can replace X with any number (number of years) to find the population in the future (positive number) or in the past (negative numbers).

Read More
705 Words | 3 Pages

The Schild plot is a method of receptor classification, measuring the affinity of antagonists to its receptors given that the antagonist is competitive. It gives a fitted regression line, which is used to estimate the pA2, the negative log of antagonist concentration, which provides 2-fold shift in

Read More
1346 Words | 6 Pages

2.60×10-3 56 5.25×10-5 59 9.50×10-3 58 5.31×10-7 60 3.23×10-3 57 1.20×10-5 60 5.02×10-4 58 -l0g A1= 10-8=8 -log A2= 10-7=7 -LOG A3= 10-6=6 -log A4= 10-10=10 (ECR) For Drug1 = ED 50 (A1)/Control = 3/3=1 E.CR For Drug 2= ED 50 (A2)/ control = 6/3=2 E C R for drug 3 = ED50 (A3) = 9/3=3 Log (ECR1-1) =1 Log (ECR2-1) = 2 Log (ECR3-1)

Read More
152 Words | 1 Pages

The purpose of the lab was to determine the relationship between time position and velocity to determine the acceleration of the pullback car. To do this, an experiment was conducted using a pullback car and video recorder to find the average acceleration of the pullback car using video analysis in the Logger Pro program. It was determined that the constant acceleration is 1.192 m/s2 and this was because it is the slope of the velocity versus time graph. In the regression equation, the acceleration was negative but that is only because the video was recorded with the lab set up backward. The starting point is 0.8221 because the instantaneous velocity of the car when the first data point was collected was 0.8221 m/s. The points on the linear

Read More
1520 Words | 7 Pages

This group’s average blood glucose to start was 94mg/dl, significantly higher than all the other groups because of their fed state. After the blood glucose was taken for this fed group, they ran for 12 minutes. At the 30 minute mark the students retook their blood sugar and saw that it went down 1% to 93mg/dl. When the blood glucose was tested at 60 minutes the blood glucose lowered to 82mg/dl with a decrease of 12%. At 90 minutes the blood glucose of the students started to rise again to 86mg/dl. Finally at 120 minutes the blood glucose rose back to

Read More
2575 Words | 11 Pages

Predict/ roughly determine the Vmax and ½ Vmax values from the peak of the graph, where the slope of the graph levels off (the asymptotical line). Predict/ roughly determine the Km by reading off of the graph the corresponding substrate concentration on the x-axis for the ½ Vmax value. Plot a Lineweaver-Burke graph (the inverse of the velocity of the reaction vs. the inverse of the substrate concentration). Calculate accurate Vmax and Km values using the following equation for the Lineweaver-Burk

Read More
1065 Words | 5 Pages

Aspirin is considered a “polydrug” due to its variety of uses stretching from pain-relief to disease prevention. Salicylic acid is derived from the bark and leaves of the willow tree. Salicylic acid belongs to a group of phytochemicals which have been shown to have positive effects on human health. Salicylic acid is a phenolic compound that can be found in a variety of plants and is a crystal organic carboxylic acid. However, it is more commonly viewed as the primary metabolite and active compound of acetyl salicylic acid, which has been used as an anti-inflammatory drug by physicians for over 100 years.

Read More
1696 Words | 7 Pages

As upper fence value is greater than maximum value there are no outliers between the maximum value and upper fence. To further investigate the outliers, normality plots can be drawn. For drug B there seem to be no outliers. This can be confirmed using normality plots. (II) Statistical Inferences and Graphical representation of data: Normality Plot: Step 1 Arrange the data in ascending order.

Read More
1539 Words | 7 Pages

Introduction The goal of the experiment is to examine how the rate of reaction between Hydrochloric acid and Sodium thiosulphate is affected by altering the concentrations. The concentration of Sodium thiosulfate will be altered by adding deionised water and decreasing the amount of Sodium thiosulphate. Once the Sodium thiosulphate has been tested several times. The effect of concentration on the rate of reaction can be examined in this experiment.

Read More
3578 Words | 15 Pages

When R2 equals 1.0, all points lie exactly on a straight line with no scatter. Knowing X lets you predict Y perfectly. (http://www.graphpad.com/guides/prism/6/curve-fitting/index.htm?r2_ameasureofgoodness_of_fitoflinearregression.htm) In this graph the R2 value is 0.97 which can be rounded off to 1.0 which means that knowing X which in this case is the different concentrations of sodium thiosulfate, predicts the Y which is the time the time the solution turns cloudy resulting X not to be seen from the opening of the conical flask from a person’s eye

Read More
788 Words | 4 Pages

Renal Resistive Index (RI) = Peak systolic velocity – End diastolic velocity Peak systolic velocity Statistical

Read More
1512 Words | 7 Pages

The mean and mode of the produced drugs will be close to the middle of the distribution curve while the standard deviation will be equal to

Read More
767 Words | 4 Pages

It was calculated and found that the concentration of benzoic acid was higher at 30℃ (0.0308M) than at 20℃

Read More

More about Salicylic Acid Investigation

Related Topics

Open Document