Stoichiometric

Stoichiometric is the study of quantitative relationships of substances in a reaction stoichiometric kimia.Dari literature means measuring elements. This term is generally used more widely, which includes an assortment pengukurab broader and includes calculations of chemical substances and mixtures.Directors stoichiometric reaction is perfect, can be calculated and measured, and does not leave the rest of the reaction (reaction low), when reacted not produce residual mole. Examples of stoichiometric reaction mixture systems NaOH - HCl is 4 ml NaOH and 4 ml HCl, 5 ml and 2.5 ml H2SO4 NaOH.Non-stoichiometric reactions are corrections that leave the rest of the overall reaction or no reaction react exhausted (no limiting reagent).The maximum point is a stoichiometric point shows the highest number of a graph between the measured properties of the quantity pereaksinya.Contoh of the maximum point on the stoichiometric system experiment was conducted 3 times with different volumes are 2ml H2SO4, 4 ml, 6ml and HCl as 6ml, 4ml, 2ml from the mixing of the two compounds produced the same temperature of the mixture that is 32 so it can not be determined maximum temperature and minimum temperature.Point or minimum point is the lowest temperature in a reaction and a point that shows the number pereaksinya quantity.Limiting reagent is the reaction of (a substance) are depleted react after experiencing a reaction process because it limits the possibility of continued reaction. Limiting reagent is determined by comparing the number of moles of each reagent according to the coefficient of the reaction and then select the value of the reagent for the number of moles of reactants and reagents terkecil.Contoh coefficient of limiting reactant in the stoichiometric system NaOH - HCl is 2 ml NaOH + 6 ml of HCl that a reagent limiting NaOH, 6 ml 2 ml HCl + NaOH the limiting reagent HCl, 2 ml NaOH + 6 ml H2SO4 is the limiting reagent 2NaOH, 6 ml NaOH + 2 ml H2SO4 is the limiting reagent H2SO4.At the stoichiometric NaOH and HCl systems, some use stoichiometric reactions and non-stoichiometric reactions. The reaction is stoichiometric reaction experiments showed 4 ml 1 M NaOH and 4 mL of 1 M HCl for pereaksinya no trace. While the reaction that shows the reaction is non-stoichiometric experiments 2 ml 1 M NaOH and 6 ml of HCl 1 M, 6 mL of NaOH and 2 ml of HCl, because pereaksinya still leave the rest.Stoichiometric chemical calculations it!
Is essentially the concept of the mole and its relationship with:
mass = moles x atomic mass or relative molecular
volume (STP) = moles x 22.4 liters / mol
pressure = (moles x 0082 L.atm / mol.K x temperature) / volume
number of particles = mol x 6:02 x 10 ^ 23
concentration = moles / volume of solution
etc..

 Stochiometric is fundamental in the study of chemistry, particularly concerning the quantity of the substance involved both before and after reaksi.Stokiometri is a comparison of the relative reaction to the formation of compounds or substances and elements. The fundamental concept is the concept of stoichiometric mole. From the concept of the mole, Stokiomeri can be used for molecular weight measurement, weight and weight of equivalent elements. Of moles can be known how many atoms or molecules are present in a solution or some volume of a gas at a certain temperature. From the concept of the mole can also be written chemical equation that occurs between two objects element or compound.A chemical equation is clearly summarize the information about the substances involved in the corrections. This equation is not simply a qualitative statement describing how much of the reactants and reaction products involved.There is one very easy way to learn some stoichiometric reactions, namely the continuous method. By varying the molar quantities, pereaksinya be changed while kuantias molar fixed, then observed his physical one. One of the particular physical properties dipikih to be examined, such as Mass, time, volume, temperature, or absorption. Therefore kuntitas pereaksinya different, then the price perubaha physical properties of this system can be used to menghitun stoichiometric system.The experiment itself is done in order to understand the concept of stoichiometric practitioner in that practitioner langsung.Selain can also determine the reaction is stoichiometric or non stokioketri and can also determine the maximum and minimum points on a stoichiometric system.
 Stoichiometric or count the ways chemistry is calculation oriented fundamental laws of chemistry. Be aware with the size of the material being studied in chemistry is so very small, so there is a special unit for the amount or concentration of a substance. Besides, an element has a period of relative atomic (Ar) nor typical relative molecular mass (Mr) of a compound and all of this related to the concept of the mole.

	Examples of questions:1. What percentage of the levels of calcium (Ca) in calcium carbonate? (Ar: C = 12; O = 16; Ca = 40)Answer:1 mol CaCO, containing 1 mol Ca + 1 + 3 mol C mol OMr CaCO3 = 40 + 12 + 48 = 100So the level of calcium in CaCO3 = 40/100 x 100% = 40% 2. A total of 5.4 grams of aluminum metal (Ar = 27) was treated with excess dilute hydrochloric acid according to the reaction:2 Al (s) + 6 HCl (aq)    2 AlCl3 (aq) + 3 H2 (g)How many grams of aluminum chloride and how many liters of hydrogen gas produced at standard conditions? Answer:Of the equation can be expressed2 mol Al x 2 mol AlCl3   3 mol H25.4 grams of Al = 05/04/27 = 0.2 molSo:AlCl3 formed = 0.2 x Mr AlCl3 = 0.2 x 133.5 = 26.7 gramsThe volume of H2 gas produced (0o C, 1 atm) = 3/2 x 0.2 x 4.22 = 6.72 liters 3. An iron ore contains 80% Fe2O3 (Ar: Fe = 56, O = 16). Oxide is reduced with CO gas to produce iron.How many tons of iron ore required to make 224 tons of iron?Answer:1 mol Fe2O3 contains 2 mol Fethen: mass Fe2O3 = (Mr Fe2O3 / 2 Ar Fe) Fe = mass x (160/112) x 224 = 320 tonsSo the iron ore required = (100/80) x 320 tons = 400 tons 4. To determine the crystal water 24.95 grams of copper sulfate salt crystal is heated until all the water evaporates. After heating the salt mass to be 15.95 grams. How much water is contained in the crystal salt?Answer:suppose formula is CuSO4 salt. xH2OCuSO4.  xH2O CuSO4 + xH2O24.95 grams of CuSO4. xH2O + 18x = 159.5 moles15.95 grams CuSO4 = 159.5 mol = 0.1 molaccording to the above equation can be stated that:number of moles of CuS04. CuSO4 xH2O = mol; thus equation24.95 / (159.5 + 18x) = 0.1  x = 5So the formula is CuS04 salt. 5H2O Empirical Formula and Molecular Formula The empirical formula is the simplest formula of a compound.This formula simply states ratio of the number of atoms contained in the molecule.The empirical formula of a compound can be determined if known one:- Ar mass and each element-% Ar mass and each element- Ar mass ratio and each element Molecular formula: if the empirical formula is known and it is also known to Mr formulas can be determined.Example: A compound C den H contains 6 grams of C and 1 gram H.Determine the empirical formula and the molecular formula of the compound where it is known Mr = 28!Answer: moles C: moles H = 6/12: 1/1 = 1/2: 1 = 1: 2So the empirical formula: (CH2) nWhen Mr compound = 28 then: 12n + 2n = 28   14N = 28 n = 2So the molecular formula: (CH 2) 2 = C2H4Example: For a 20 ml oxidize hydrocarbons (CxHy) required oxygen in a gaseous state as much as 100 ml and 60 ml of CO2 produced. Determine the molecular formula of the hydrocarbon?Answer: hydrocarbon combustion equation in generalCxHy (g) + (x + 1/4 y) O2 (g)    x CO2 (g) + 1/2 y H2O (l)The coefficient indicates the reaction mole ratio of the substances involved in the reaction.According to Gay Lussac gases on p, t the same time, the number of moles is proportional to the volumeThen:CxHy mol: mol O2: mol CO2 = 1: (x + 1/4y): x20: 100: 60 = 1: (x + 1/4y): x1: 5: 3 = 1: (x + 1/4y): xor:1: 3 = 1: x    x = 31: 5 = 1: (x + 1/4y)    y = 8So hydrocarbon formula is: C3H8