USING ENGLISH TO PREDICT RENDEMENT OF PRODUCT OF REACTION

RENDEMEN

        Rendement is actually a term in the field of chemistry studies. The yield represents the inaccuracy of the reaction result, which results always lower than the mathematical calculation. For example, in a chemical reaction, should produce a substance weighing 100 grams, mathematically, but in reality the results obtained only 90 grams. Unconsciously this also often happens in our daily live.

          The mixture is a composite of two substances or more which are not chemically united or their constituent substances still retain their respective properties. Various mixtures of biases are grouped into two types: homogeneous mixtures and heterogeneous mixtures.

           Actually what is a homogeneous mixture ??? Homogeneous mixture is a mixture of two types of substances or more that can not be seen again the boundary plane between the substances mixed. The border field can not be visible even if viewed with a microscope. A homogeneous mixture is often also referred to as a solution. For example, air is a mixture of various types of gas.

      While the heterogeneous mixture is a mixture of two or more substances that still visible the boundary plane. For example a mixture of water with oil.

The mixture is a collection of various molecules, substances, ions, electrons, and other particles. We can measure pressure, volume, temperature and mixed mass. We can also measure the composition of the mixture experimentally so that the fraction of moles and masses can be determined (Sulistiati, 2013: 39).

A mixture is classified as heterogeneous and / homogeneous. The heterogeneous mixture is composed of individual phases, and the observed properties are composite rather than single phases. A homogeneous mixture comprises a single phase having properties very different from its sole components. The solution is defined as a homogeneous substance which is a mixture of two or more components which may be gaseous, liquid, or solid. The gas solution is made by mixing one gas in another. Since all the gases are mixed in all comparisons, each gas mixture is homogeneous and it is a solution (Sastrohamidjojo, 2005: 227).

If two different substances are inserted in one container there are 3 possibilities, which are mixed, reacted and unmixed. If the substances are mixed, the properties of the substance are immutable and can be separated by physical means, such as distillation, crystallization, chromatography, and so on. On this earth rarely found pure substance, generally a mixture. Two or more substances are called mixed, when the particles are dispersed in the same container so that they are in contact with each other. Two substances can be mixed when there is a reaction between the particles. The interaction is determined by the nature and nature of the substance. Therefore, the mixture can be divided into: a mixture of gases with gases, gases with solid, liquid with liquid, liquid with solid, and solid with solid (Syukri, 1999: 350-351)

3.1 Tools and materials

 Tools:

1) The vapor plate

2) Balance Sheet

3) Bunsen

4) Measuring cups

5) Glass watch

6) Chromatographic vessel

7) Trophy glasses

8) Scissors

9) Filter paper

10) Penotol (capillary pipe)

11) The gull

12) Pipette drops

13) Three-legs

14) Gauze

             Material:

      1) 0.1 gram of NH4Cl

      2) 0.1 gram NaCl

      3) 0.1 gram of SiO2

      4) 100 ml of distilled water

      5) Eluen solvent = mixture of butanol,                   a    cetic acid, water (1: 1: 4)

      6) 1 gram of BaCl2

     7) 25 ml of K2CrO4

     8) A mixture containing BaCl2

 Analysis through precipitation

A. Percentage of chromate barium yield

1.      Prepare a cup

2.      Weighed

3.      Added 1 gram of BaCl2

4.      Added 25 ml of distilled water

5.      Stirred until homogeneous

6.      Added 2 ml of K2CrO4 0,2 M

7.      Stirred and observed precipitate formed

8.      Heated

9.      Filtered with Wathman filter paper

10.  Dried, weighed, recorded the weight

11.  The theoretical results of sediment and percent yield are calculated

The weight of the sediment BaCrO4: 4.74 grams

Percent yield BaCrO4: 467%

 Analysis through precipitation

A. Percentage of chromate barium yield

A mixture consists of solution, colloidal, and suspension. In the presence of colloidal and suspension, it may allow precipitation if left long or precipitated by K2CrO4. The data in this experiment was obtained from experimental data in the physics physics education pgmipau 2014 report. This is because we can not conduct the experiments caused by the power failure so we can not do the weighing of substances and tools.

The procedure that should be done is to weigh the cup. Then weigh the cup of the cup containing BaCl2, which is 92.7 grams. The mass of BaCl2 is 0.7 grams. 25 ml of distilled water is added and stirred until homogeneous. Added 25 ml of K2CrO4 0.2 M, stirred and then observed the precipitate formed. K2CrO4 is a precipitation indicator. K2CrO4 makes the coarse particles in the mixture precipitate and form a clear solution so that the bottom can be a precipitate and the top can be a clear solution. When the sediment of BaCrO4 is still formed, K2CrO4 is added again until the precipitate is no longer formed. Then heated to boiling and filtered with Whatman filter paper. The precipitate is dried and weighed 4.74 grams. From the data can be calculated percentage of BaCrO4 that is 467%.

In this experiment there may be a slight error because the yield percentage exceeds 100%. In theory, if barium chromate is perfectly settled then the percentage is 100%. This difference in yields may occur because of the lack of additional K2CrO4 and in the less drying process.

How to determine the percentage of barium chromate in the mixture ie

% BaCrO4 = mass of sediment on practice / mass of the original example x 100%.

 Analysis through precipitation

A. Percentage of chromate barium yield

1) Trophy weight + BaCl2 = 92.7 grams

2) Trophy weight = 92 gram

3) Weight BaCl2 = 1-2 = 0.7 grams

4) The weight of the filter paper + sediment BaCrO4 = 6.48 grams

5) The weight of filter paper = 1.74 grams

6) Weight of sediment BaCrO4 = 4-5 = 6.48 - 1.74 = 4.74 grams

7) Percent of results BaCrO4

A. BaCrO4 masses theoretically

N BaCl2 = 0.7 g / 208 = 0.0033 mol

BaCl2 + K2CrO4 → BaCrO4 +2 KCl

0.0033 mol 0.0033 mol

G BaCrO4 = mol x Mr = 0.0033 mol x 253 = 0.8349 grams

B. Percent BaCrO4 = (g theoretical precipitate) x 100%

G theoretical

= (4.74 - 0.8349) x 100%

0.8349

= 467%