PRAKTEK PGMI REGULER UJI BAHAN MAKANAN

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UJI BAHAN MAKANAN
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Experiment II Steam distillation

Experiment II

Steam distillation

Steam distillation is a special type of distillation (a separation process) for temperature sensitive materials like natural aromatic compounds. Many organic compounds tend to decompose at high sustained temperatures. Separation by normal distillation would then not be an option, so water or steam is introduced into the distillation apparatus. By adding water or steam, the boiling points of the compounds are depressed, allowing them to evaporate at lower temperatures, preferably below the temperatures at which the deterioration of the material becomes appreciable. If the substances to be distilled are very sensitive to heat, steam distillation can also be combined with vacuum distillation. After distillation the vapors are condensed as usual, usually yielding a two-phase system of water and the organic compounds, allowing for simple separation.

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Experiment III-DETERMINATION OF ACTIVATION ENERGY & A REACTION RATE CONSTANT

Experiment III-DETERMINATION OF ACTIVATION ENERGY & A REACTION RATE CONSTANT                                  see experiment report ......                                                                                                                                                                                                            Percobaan III-penentuan energi aktivasi dan tetepan laju reaksi                               laporan praktikum selengkapnya ......... 

ACETYLSALICYLIC ACID/ASPIRIN

Experiment VII

ACETYLSALICYLIC ACID (Aspirin)

This experiment illustrates a very useful method of acetylating phenols: the phenolic substance is suspended in acetic anhydride and a small quantity of concentrated sulfuric acid is added to serve as a catalyst. The strong mineral acid is very effective in accelerating the reaction and frequently no external heating is required. Certain basic substances may also be employed as catalysts, the commonest ones being fused sodium acetate and pyridine (a tertiary amine). It should be observed that phenols (unlike amines) cannot be acetylated satisfactorily in aqueous solution; the hydroxyl group of a phenol is not attacked much more rapidly by acetic anhydride than is the hydroxyl group of water, with which the phenol would be competing.

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UJI VITAMIN

UJI VITAMIN

Vitamin merupakan nutrisi tanpa kalori yang penting dan dibutuhkan untuk metabolisme tubuh manusia. Vitamin tidak dapat diproduksi oleh tubuh manusia, tetapi diperoleh dari makanan sehari-hari. Fungsi khusus vitamin adalah sebagai kofaktor (elemen pembantu) untuk reaksi enzimatik. Vitamin ditemukan di berbagai jenis makanan, buah-buahan, sayur-sayuran, sereal (biji-bijian), daging, ikan dan produk-produk susu.

Vitamin juga berperan dalam berbagai macam fungsi tubuh lainnya, termasuk regenerasi kulit, penglihatan, sistem susunan syaraf dan sistem kekebalan tubuh dan pembekuan darah. Tubuh membutuhkan jumlah yang berbeda untuk setiap vitamin. Setiap orang punya kebutuhan vitamin yang berbeda. Anak-anak, orang tua, orang yang menderita penyakit atau wanita hamil membutuhkan jumlah yang lebih tinggi akan beberapa vitamin dalam makanan mereka sehari-hari.

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Physical chemistry experiment--Determination of activation energy and A reaction rate constant

Physical chemistry experiment
Determination of activation energy and A reaction rate constant

Experiment Purpose

• ·         Determine the value of activation energy for Na₂S₂O₃ (aq) with HCl (aq) reactions

• ·         Determine the value of reactions rate constant (k) in various temperature

 Introduction

Commonly, rate for the reactions affected by increase of temperature. For the common reactions, the rate increase two until three times for the temperature increase at 10 degrees. This related with the average increase of kinetic energy of the reactan because the increase of temperature that decrease barrier energy of the reaction and the reaction more easier to react. 

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PHYSICAL CHEMISTRY EXPERIMENT-ELEVATION OF BOILING POINT

PHYSICAL CHEMISTRY EXPERIMENT-ELEVATION OF BOILING POINT

Experiment purpose

Determine moleculer weight of the substance using elevation of boiling point methode

Introduction

If the solids are not easily dissolved in the solvent evaporates, the vapor pressure will eventually come down so that the boiling point of the solution will rise and its freezing point will drop compared to the pure solvent.

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