using english to predict rendement of product a reaction

Rendement 

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 lives loh.
In a chemical reaction we can always calculate the reaction results as much as 100%, but in reality it never happened in practice.

Chemistry is:

Section of natural science, studying the elements that make up all the substances / compounds that exist, that includes the structure, how the elements combine to form other substances / compounds, and how the reaction to different conditions.

Physical and Chemical Properties:

To know the properties of a compound, we need to know its physical properties, which can be observed without altering its identity, and chemical properties, which can be shown only through chemical changes.

Measurements and Units:

Chemistry is a quantitative science and requires measurement. Measurable quantities (such as mass, volume, density, and temperature) typically have their respective units. The units used in chemistry are based on international system units (SI).

Handling Numbers:

Scientific notation is used to denote small numbers and large numbers, and each number in a measurement must show, the number of digits is called a meaningful number

Graph:

Graphics are used to help organize the information, because it provides a visual representation of a topic, clearly showing how important concepts are linked.

Chemical calculation:

A simple and effective way to perform chemical calculations is the conversion factor method, which is based on dimensional analysis.

DIAGRAM A GENERAL WAY TO FULLY PROBLEM STOIKIOMETRY INVOLVING A CHEMICAL REACTION

GRAM ZAT A  ® MOL ZAT A  ® MOL ZAT B ® GRAM ZAT B

  1 mol A / g A            of the mol ratio      B x Gr B / mol

 (X 1 / molar mass)      mole coefficient A      (x molar mass B)

                                   To mol B

Evaluation Of Success Reaction

Theoretical Rendemen A Particular Product Is

The maximum result obtained if the reactants only produce the product without side reactions

REAL RENDEMEN is the number of products actually gained in an experiment

In chemistry, the chemical yield, the yield of the reaction, or only the rendement refers to the amount of reaction product produced in the chemical reaction. [1] Absolute rendement can be written as weight in grams or in moles (molar yield). The relative yield used as a calculation of the effectiveness of the procedure is calculated by dividing the amount of product obtained in moles by the theoretical yield in moles: 

To obtain a percentage yield, multiply the fractional yield by 100%.

One or more reactants in chemical reactions are often used redundantly. The theoretical rendement is calculated based on the number of moles of the limiting reagent. For this calculation, it is usually assumed there is only one reaction involved.

The ideal chemical yield value (theoretical rendement) is 100%, a value highly unlikely to be achieved in its practice. Calculate the percentage of rendement that is by using the following equation percent rendemen = weight yield / weight of yield divided by the sample weight multiplied 100%.

Chemical Reactions

a. Burning Reactions

Is a reaction between a substance with oxygen to produce substances that are new and hot. Combustion reactions may also cause fire, explosion, or only cause fl uor.

Fuel combustion generally generates carbon dioxide gas, water vapor and some energy. Examples such as fuel combustion in a motor vehicle.Pentanes are burned to produce carbon dioxide gas and water vapor

B. Combination Reactions

Combination reactions are often referred to as oxidation-reduction reactions or redox reactions which are free elements.In the oxidation reaction can be found when two or more reactants become new substances. An example of a coupling reaction is for example the reaction between iron with sulfur (sulfur) which produces iron sulphide and zinc compounds with sulfur heated to zinc sulphide.

 Oxidation reaction also takes place in the process of respiration that is the process of oxidation of glucose in the body of living things.

Reduction reaction occurs when a substance loses oxygen. This reaction is usually used to extract metals from the ore.

 c. Decomposition Reactions

In the decomposition reaction that occurs is the opposite of the merging reaction. Where a substance decomposes into two or more new substances. Examples of decomposition reactions eg in the process of electrolysis water into hydrogen gas and oxygen gas using electricity, the reaction is as follows:

d. Replacement Reactions

Reaction reactions can be divided into two kinds: single replacement reactions and multiple replacement reactions.

1. A single replacement reaction occurs when an element replaces the position of another element in a chemical reaction, For example in the reaction between the copper wire dipped in the silver nitrate solution. Since copper is more active than silver, copper replaces the silver position to form a blue copper (II) nitrate solution.

 2. Double replacement reactions can occur in ionic interchange of atoms or compounds such as in the reaction process between hydrochloric acid (HCl) and sodium hydroxide (NaOH) to produce the salt of the kitchen (NaCl) and water (H2O).

e. Metathesis reaction,

consisting of:

• depositional reaction; A reaction process that forms a precipitate, as in the reaction between lead (II) nitrate and potassium iodide yields a yellow sized lead (II) iodide and a solution of potassium nitrate

 • neutralization reaction; Is a reaction between acids and bases that produce salt and water

• gas formation reaction; Is a chemical reaction in the gas produced product

• in the fermentation process involving microorganisms, ie yeast. In baking, yeast added to the dough will cause the bread dough to expand. Because carbon dioxide is formed when baking soda (NaHCO3) is added to the dough and the roasting process causes the yeast cells to die, the fermentation process stops.

• ferrous metals can react quickly with hydrochloric acid (HCl) to form iron (II) chloride (FeCl2) and hydrogen gas (H2)

Example Problem-1:

A reaction takes place according to the following reaction equation:

2Al + 3Cl₂ → 2AlCl₃

a. Available 1.2 mol of Al and 2.4 mol of Cl2 what substance acts as a limiting reagent and what is the residual unreacted substance based on the equation of the reaction?

b. Available 1.2 grams Al and 2.4 grams of Cl2, what substance acts as a limiting reagent and what is the residual unreacted substance based on the equation of the reaction?

Solving Problem-1a.

If the data is given in units of moles for each substance, it can be used directly to determine which limiting reagent and how much of the unused substance in the reaction. Based on the equation of the reaction which has equalized the number of elements on the left and right of the arrow then the ratio of the number of moles of Al and Cl2 reagents is 2: 3. Remember that the mole ratio will be proportional to the ratio of the equivalent coefficient of each substance. Check the mole ratio with the coefficients of each reactant:

2Al → 1.2 mol ÷ 2 = 0.6 mol

3Cl2 → 2.4 mol ÷ 3 = 0.8 mol

The smallest comparison ratio (Al = 0.6 mol) will be exhausted first and Al is the limiting reagent.

Cl2 reacted = 0.6 mol × 3 (3 → coefficient Cl2) = 1.8 mol.

Cl2 that does not run out = 2.4 mol - 1.8 mol = 0.6 mol.

Solving Problem-1b:

Since the data presented in grams can not be solved directly, it is necessary to convert grams to moles first.

1.2 g Al = 1.2 g ÷ 27 g / mol = 0.044 mol Al

2.4 g Cl2 = 2.4 g ÷ 71 g / mol = 0.033 mol Cl2

Check the mole ratio with the coefficients of each reactant:

2Al → 0.044 mol ÷ 2 = 0.022 mol

3Cl2 → 0.033 mol ÷ 3 = 0.011 mol

The smallest comparison ratio (Cl2 = 0.011 mol) will be exhausted first and Cl2 is the limiting reagent.

The exhausted Al = 0.011 mol x 2 (2 → Al coefficient) = 0.022 mol.

The unreacted Al = 0.044 mol - 0.022 mol = 0.022 mol Al

0.022 mol Al = 0.022 mol × 27 g / mol = 0.594 g