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Orgo discussion

Submitted by kmydosh on Fri, 11/17/2017 - 11:28

In this lab trimyristin was synthesized from nutmeg and myristic acid was synthesized from trimyristin. Trimyristin was recrystallized twice to obtain as pure of a sample as possible. Myristic acid was obtained by hydrolysis. The final product was obtained by suction filtration. The product was weighed and its purity assessed by melting point. The product was identified to be trimyristin which after its 2nd recrystallization had a melting point of 56° C. The melting point of myristic acid was found to be 54° C. The percent yield for the first recrystallization of trimyristin was 18%.  In future experiments extra time should be allowed for the cooling of the flask to room temperature so that as many crystals can form as possible. After the 2nd recrystallization of trimyristin the percent yield was 73%.  The final melting points of 56° C for trimyristin and 54° C for myristic acid confirms the identity of these products.  

Trimyristin Synthesis

Submitted by kmydosh on Thu, 11/16/2017 - 11:02

In this experiment nutmeg (1.00 g), tert-buyl methyl (3.0 mL), and three boiling chips was added to a round bottomed flask. This solution was heated gently at just its boiling point for 10 minutes. This was then allowed to settle for 3 minutes. The liquid layer on top was then microfiltered. Fresh tert-buyl methyl (2.0 mL) was then added to the round bottomed flask and was boiled, then allowed to settle for three minutes again. The microfiltration of the liquid layer on top was repeated. The microfiltered liquid was all collected in a 25 mL Erlenmeyer flask and air was gently blown over the solution till all of the solvent evaporated. Acetone (1 mL per 50 mg of crude material) was then added to the 25 mL Erlenmeyer Flask. This was then recrystallized and the solid collected vis suction filtration. Trimyristin (63 mg) was then added to a round bottomed flask with NaOH (2 mL, 2 M), ethanol (2 mL, 95%), and three boiling chips. This solution was then refluxed for 45 minutes. While this process was underway the trimyristin was recrystallized a second time. Once hydrolysis had completed, the flask was allowed to cool to room temperature and the contents were poured into a 50 mL beaker with water (8 mL). HCl (2 mL) was then added to this dropwise while also stirring. This was then cooled in an ice bath for 10 minutes and the product was then collected by suction filtration. The identity and purity of the products were then assessed. 

Physics Conclusion

Submitted by kmydosh on Thu, 11/16/2017 - 11:01

In this lab we used a direct circuit power supply and the PASCO 550 interface to explore simple circuits. We found that circuits in series use less power than circuits in parallel using the equation P = V1. The calculations in question 8 show that a circuit in series uses 0.133W while a series in parallel uses 0.506W. We also demonstrated how the circuits followed Ohm’s law, V = IR, which says that resistance is linear when comparing voltage vs. current. This is demonstrated in the graph from question 1. This experiment successfully confirmed the given equations and explored how to connect a circuit in parallel and series.

Area 4 and 6

Submitted by kmydosh on Sat, 11/11/2017 - 22:00

Area 6 of the motor cortex is primarily involved in the planning of executing a physical action. Area 4 is involved in the actual execution of the action. An experiment with a money demonstrates this. The monkey must touch a certain button only after the button lights up. A light above the correct button lights up but the monkey can only get the reward when the button itself lights up. The light above the button is the instruction stimulus. The button itself lighting up is the trigger stimulus. Before any lights are on the neurons in Area 6 are not firing. When the instruction stimulus comes on the Area 6 neurons start to fire. When the trigger stimulus is on the neuron fires and then gradually stops. Meanwhile, when the Area 6 neurons stop firing as radidly, the Area 4 neurons start firing as the monkey executes the task of touching the button. This experiment demonstrates what areas of the motor cortex are involved in moving. 

Physics notes

Submitted by kmydosh on Fri, 11/10/2017 - 19:39

Accommodation

Ciliary muscles around lens change its shape and focal length

Eye’s lens changes shape (changes f ) to focus on objects near and far, Object at any do should produce image at retina (di ≈ 2.0 cm) Lens can only change shape so much • “Far Point” Furthest do where image can be at retina Normally, dfar = ∞ (if nearsighted then closer) • “Near Point” Closest do where image can be at retina Normally, dnear ≈ 25 cm (if farsighted then further)

Myopia: Nearsightedness. If nearsighted, far point dfar < ∞. Object at do > dfar creates image in front of retina. Corrective lens creates image of distant object at the far point of the nearsighted eye. flens such that distant object at ∞ (“normal” far point) is in focus. Flens=-dfar. Negative for diverging lens.

Hyperopia: Farsightedness: If farsighted, near point dnear > 25 cm. Object at do < dnear creates image behind retina. Corrective lens creates image of close object at the near point of the farsighted eye. Flens such that object at 25 cm (“normal” near point) is in focus. Dnear>25cm so flens >0 for converging lens.

Refractive power: Use P=1/f. Units are in diopters. 

Neuro Notes Chapter 13

Submitted by kmydosh on Thu, 11/09/2017 - 11:24
  • The structure of skeletal muscles
    • T tubules: spread excitation
      • Talking about calcium again
      • The calcium is in high ammounts inside the muscle
    • Muscle fiber is encased in a
    • Bottom line changes in volatage spread through the muscle fiber and open up ca channels and release calcium
    • Calcium release allows the actin and myosin fibers to slide against eachother
      • Heads of myosin walk along the actin in response to the calium
      • Calcium present allows the myosin to come into contact with the actin
    • The trigger is calcium and it is able to have its effect
    • Troponin
  • Proprioception
    • Sense of knowing where your body is in space
      • Two different sensors
        • Muscle spindles
        • Golgi tendon organs 

Physics Conclusion

Submitted by kmydosh on Thu, 11/09/2017 - 11:24

In this experiment we used probes to measure electric potential between two charged contacts and visualize electric fields. Various charges and directions were mapped with the two probes to map the electric field. To map equipotential lines five different points were located for 2V, 3V, and 4V. A pattern can be seen forming around the positive and negative contact points on the electric field board. Each point at an equipotential line has the same value. The patterns mapped on the board were consistent with the map of the electric field shown in lab. 

Abstract

Submitted by kmydosh on Thu, 11/09/2017 - 11:23

In this lab we used a field mapping board to explore how direction and strength of an electric field changes using field probes. Two points of contact stick up from the board. Red corresponds to positive and black to negative charges. An electric field is created on the black mapping paper when the contacts are charged. During this experiment we used the field probes and voltmeter to map the electric field on the black piece of paper and corresponding printed out paper. The spacing between the probes was approximately 1.0 cm. This allowed us to see the overall shape of the electric field. The power was first set to 2V DCV and then for the second test it was set to 20V DCV. The patterns of the electric field and equipotential lines were then assessed. 

Discussion

Submitted by kmydosh on Wed, 11/08/2017 - 12:59

In this experiment butyl naphthyl ether was synthesized by an SN2 reaction from 2-napthol. The product was washed and dried with ice-cold water and filtration suction for 25 minutes. The product was obtained by using the technique reflux. The percent yield was calculated to be 50.5%. The yield could have been affected during the process of stirring the ice cold mixture if the solution was brought close to room temperature while the ice melted or during the filtration suction. The melting point was observed to be 97°C. The product was identified by TLC analysis. The TLC plate run using a solution of 75 hexane to 5 EtOH was the most effective ratio. In this TLC plate the starting material is shown lower on the plate with a smaller Rf value of 0.625. The starting material and filtered solid show two spots clearly. The first spot is in line with the starting material with a Rf value of 0.625 and the second dot has an Rf value of 0.938. The last spot shown is the filtered solid, the product, with an Rf value of 0.038. For TLC analysis non-polar compounds move up the plate more rapidly resulting in a higher Rf value while polar compounds travel up the plate more slowly resulting in a lower Rf value. 2-napthol is a polar compound and as expected it has a lower Rf value of 0.625 than the product which is non-polar and has a higher Rf value of 0.938. This is how the identity and purity were assessed. 

Experimental Procedure

Submitted by kmydosh on Wed, 11/08/2017 - 12:58

In this experiment, sodium hydroxide (0.64 g, 1 M), 2-napththol (0.200 g, 1 M) and a few boiling chips were added to a round-bottomed flask (10 mL). Absolute ethanol (3 mL) was then added to the round bottomed flask as well. The contents of th   e round bottomed flask were then refluxed for 25 minutes. After 25 minutes the solution was cooled for 3 minutes. N-butyl iodide (0.200 mL) was then added through the top of the condenser. The solution was then refluxed for 1 hour. The mixture was then poured over ice (10 g) rinsed with ice cold water. The reaction mixture was then stirred with a glass rod till 95% of the ice melted. Then the product was dried by suction filtration for 25 minutes and rinsed again with ice-cold water. The product was the further analyzed by TLC analysis. The first TLC analysis used a ratio of 75 hexane: 5 EtOH and the second trial used a ratio of 5 hexane: 75 EtOH. 

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