Jumat, 19 Mei 2017

Rendement



Rendement of starch contained in the tubers

In chemistry, the chemical product, the reaction product, or only the rendement refers to the amount of reaction product produced in the chemical reaction. Absolute rendement can be written as weight in grams or in moles (molar yield). The relative results used as the calculation of the effectiveness of the procedure, calculated by dividing the number of products obtained on the mole with theoretical results on the mole: fractional yield = actual results Theoretical yield / initial yield multiplied 100% To obtain Percentage yield, multiply the fraction by 100%. One or more reactants in chemical reactions are often overused. Theoretical rendement is calculated by the number of moles of the limiting reagent. For this calculation, it is usually assumed that there is only one reaction involved. The ideal chemical yield value (theoretical rendement) is 100%, a very unattainable value in practice.



To exemplify the calculation I use the results of the experiment Nober Bumbungan on Wednesday, November 16, 2011.

A.    Methodology
Tools and materials
Tools:

  1. The reaction tube                  
  2. Blender
  3. Stirring rod                                
  4. Measuring cups 
  5. Oven
  6. Grated
  7. Glass watch
  8. Hot plate
  9. Pipette drops
  10. Glasses of chemicals
  11. Mortar and pestle

Materials :
  1. Filter cloth                                
  2. Potatoes 
  3. Sweet potatoes                      
  4. Iodine solution 1%
  5. Aquades                                  
  6. Corn
       B.     Work Procedure
           a.      Separation of starch
1) Weighing 125 grams that have been smashed with grated.
2) The crushed material is inserted into a 500 ml glass of chemicals and homogenesis by well stirring then filtered with a filter cloth.
3) Filtrates obtained from filtrate are allowed for some time Until the seal settles.
4)  Separates the precipitate and filtrate by decantation.
5) The precipitate obtained is added again with water and stirred, after it is decanted again 3 times.
6) Transferring the precipitate on the glass of the watch previously known to the weigh.
7) The deposits contained on the watch glass Dried in oven at 105 ° C to dry (not sticking to finger).
8)  Weighing the watch glass and calculating the randemen of the starch obtaine.
9)  Calculating the formula with the formula.


   
ket:
a = The sample weight in the material
b = Weight of watch glass 
c = Weight of watch glass containing sediment

b.      Amylum Test
1)      Taking a little precipitate obtained in experiment 1 inserted into the test tube and then added with 2 ml aqades.
2)      Adding a 1% iodine solution is shuffled and observed changes occur.


C. Observation Results 
a.      Separation of starch
No.
Sample
Weight watch glass

Weight of blank watch glass + sediment
1
Cassava
18.4 gr
23,88 gr
2
Potato
18.4 gr
28,9 gr
3
Corn
18.4 gr
26,7 gr
4
Sago
18.4 gr
25,9gr

b.      Amylum Test
No.
Sample
Color

Color after addition of iodine solution
1
Cassava
white
Dark blue
2
Potato
Brown
purple
3
Corn
yellow
purple
4
Sago
Cloudy white
purple

  D.    Data analysis
Formula:
ket:
a = The weight of the sample in the material
b = Weight of blank watch glass
c = The weight of the watch glass contains the sediment 



E. Discussion
Carbohydrates are aldehyde polihydrate compounds which are polymers of monosaccharides with the formula molecule Cn (H2O) n. In carbohydrates are the synthesis of molecules of CO2 and H2O with the help of sunlight and green leaf substances (chlorophyll), known as the synthesis photo process. In this treatment all the material is peeled, crushed and weighed 125 grams, the purpose of which is destroyed by the material to expand the surface plane for easy extraction of the four materials. Then from each of these ingredients are inserted into a 500 ml kimi glass and added with 100 ml of water and well stirred. It is intended to mix and dissolve in water because water is a good solvent for starch because the starch has a hydroxyl group attached to a hydrogen atom of water. Then done the decantation process twice that serves to obtain the essence or starch of each ingredients. The precipitate of the obtained starch was dried by oven at 105 ° C to remove the water content contained in each ingredient. After drying the precipitate of the starch is calculated percent of rendement of each material. Based on the result of calculation from percentage of starch, it was found that the yield of starch was 4.32%, potatoes 8.4%, corn 6.64% and sago 6%. From the results of the calculation of rendemen is not in accordance with the literature, According to (Anonymous, 2011) percent of the yield of starch that is in cassava is 55%, 59.7% potatoes, 59.5% corn and sago 59.8%. Differences in the yield of starch obtained by the literature due to inaccuracy. In this experiment also performed a starch test using 1% iodine from each ingredient is added 1% iodine so that the cassava yield is initially white to be dark blue, the potato is initially brown to purple, the corn which originally yellow into purple and the sago Initially turbid white to purple. From the results of color changes in accordance with the literature that states that the starch hydrolyzed polysaccharides will form a dark blue to purple. 

F.      Conclusion
From the experiment result can be concluded as follows:
·         Carbohydrates are polyhydroxy aldehyde compounds which combine monosaccharide polymers with the formula of molecules Cn (H2O) n.
·         Amount of cassava yield obtained was cassava 4.32%, potato 8.4%, corn 6.64%, sago 6%.

15 komentar:

  1. Why do we need to learn this? Is there any effect on the next lesson?

    BalasHapus
    Balasan
    1. We study this in order to know the amount generated from the level of productivity of a chemical reaction. Yes of course, so we understand the subject matter that will be delivered in class tomorrow morning. As we know we are required to be able to predict the likelihood of rendemen formed from a reaction in English.

      Hapus
  2. Give examples of problems and solutions for Separation of starch

    BalasHapus
    Balasan
    1. For example the separation of starch in tapioca-making technique through Precipitation / Sedimentation, that is by:
      In the precipitation is meant to separate pure starch from other parts as a soluble contaminant. Precipitation can be done in the settling tank. To accelerate the deposition of starch granules are often added certain chemicals such as sulfuric acid, aluminum sulfate, sulfur dioxide or chlorine. In addition to the substances it helps the settling also helps the bleaching process of starch later. Starch granules measure between 4-24 microns. The precipitation is highly dependent on the diameter of the starch granules, the acidity of the medium (the immersion water), the inherent protein content, and other colloidal agents. Precipitation will generally run for 24 hours resulting in a sediment thickness of approximately 30 cm.

      Hapus
  3. How to determine barrier reagent?

    BalasHapus
    Balasan
    1. How to determine the barrier reagent that is, if the number of known reacted moles divided by the coefficient of the reaction equation gives less value than the other reactants, the reagent is a limiting reagent. The limiting reagent will be exhausted therefore remaining after the ending reaction is not a limiting reagent and the number of other reactants reacting equally to the number of moles of the limiting reagent.

      Hapus
  4. Separate the sediment and filtrate by decantation, how the decantation process?

    BalasHapus
    Balasan
    1. A mixture of insoluble solids in the liquid is allowed for a moment. The solid is insoluble and will settle below if the mixture is kept within a certain time, then the liquid separated from the sediment is transferred into another vessel. This process is called decantation.

      The centrifugation device may be useful in decanting the solution, if the density of the species and by the particle size to be separated is relatively small so that some floating or floating solids. The centrifuge may cause the precipitate to be forced to settle under the vessel; If strong enough, the precipitate can coalesce and precipitate into a solid collection. Then the desired filtrate can be easily removed, since the precipitate will remain in a compressed form. [2]

      Similarly, a mixture of non-soluble liquids can also be separated by decantation techniques.

      Hapus
  5. In the discussion forum there is a separation of a material by extraction. Can used separation of a substance other than by way of extraction? give the reason

    BalasHapus
    Balasan
    1. in my opinion is not the same, because the separation used in addition to the eltraction will give different result. often extraction is also accompanied by chemical reactions. in this case the material to be separated must be absolute in the form of solution. boiling point since extracts and solvents usually have to be separated by evaporation, distillation or rectification, the boiling points of both materials should not be too close, and they do not form ascotrops.

      Hapus
  6. What materials produce the highest percent of yield?

    BalasHapus
  7. "The starch test: Adding a 1% iodine solution was shaken and observed a change in" what is the added function of iodine solution in the above experiment?

    BalasHapus
    Balasan
    1. Iodine solution is used to test carbohydrate content of a food. If there is then the food after the drop will be purple.

      Hapus
  8. How to process decantation?

    BalasHapus
    Balasan
    1. A mixture of insoluble solids in the liquid is allowed for a moment. The solid is insoluble and will settle below if the mixture is kept within a certain time, then the liquid separated from the sediment is transferred into another vessel. This process is called decantation.

      Hapus

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