ATOMIC STRUCTURE

ATOMIC STRUCTURE
A. BASIC UNDERSTANDING
1. Elementary particles: particles are composed of atoms forming
electron, proton neutron den.
1. Proton: forming atomic particles have the same mass
one sma (amu) and charged +1.
2. Neutron: particles forming a sma atomic mass (amu) and
neutral.
3. Electron: atom forming particles that have no mass and
charged -1.
2. The nucleus: a positively charged nucleus, consisting of protons den
neutrons.
3. Notation elements: z
A A to X: sign atoms (elements)
Z: atomic number = number of electrons
(E)
= Number of protons (p)
A: mass number = number of protons +
neutron
In neutral atoms, applies: the number of electrons = number of protons.
Example:
1. Determine the number of electrons, protons neutrons den of element 26
56 Fe!
Answer:
The number of electrons = number of protons = atomic number = 26
Number of neutrons = mass number - atomic number = 56-26 = 30
2. Give notation elements of X, given the number of neutrons = 14 and
number of electrons = 13!
Answer:
Atomic number = number of electrons = 13
Mass number = number of protons + neutrons = 13 + 14 = 27
So the notation elements: 13
27 X
4. No neutral atoms: electrically charged atoms due to excess or
electron deficiency when compared with the neutral atom.
Positively charged atoms when the electron deficiency, called cations.
Negatively charged atoms when an excess of electrons, called anions.
Example:
- Na +: cation with one electron deficiency
- Mg2-: cation with a shortage of 2 electrons
- Cl-: anion with an excess of one electron
- O2: anion with an excess of two electrons
5. Isotopes: elements of the same atomic number, but different numbers
mass.
Example: oxygen isotopes: 8
16 O: 8
17 O: 8
18 O
6. Isobar: elements of the same mass number, but different numbers
atom.
Example: 27
59 CO with 28
59 Ni
7. Isoton: elements with the same number of neutrons.
Example: 6
13 C with 7
14 N
8. Iso electron: atom / ion with the same number of electrons.
Example: Na + with Mg 2 +
K + with Ar
B. MODEL ATOM
1. MODEL ATOM JOHN DALTON
- Atom is the smallest part of an element
- Atoms can not be created, destroyed, divided, or changed to
other substances
- Atoms of an element is the same in all respects, but different
atoms of other elements
- Chemical reaction is a process of merging or splitting of the atom
elements are visible
Dalton's atomic theory Weakness: can not distinguish sense
den atom molecule. And the atom was not the smallest particles.

ATOM 2.MODEL J.J. THOMPSON
- Atom is a positively charged sphere and inside spread
electrons are like raisins
- The amount of positive charge with a negative charge, so that the atoms are
neutral
3. RUTHERFORD ATOM MODEL
- Atom consists of a very small nucleus with a positive charge
mass is the mass of the atom
- Electrons moving around the nucleus in an atom is
- The number of electrons in an atom equal to the number of protons in the nucleus and
This corresponds to the number
atom
4. MODEL ATOM Bohr
According to Niels Bohr electrons can move (transition) from a lower energy level to a higher energy level or vice versa. Electrons that have the lowest energy, is on the path closest to the nucleus.
The nucleus is positively charged, have an attraction to the negatively charged electrons. As a result, the electrons in each track is always surrounds the nucleus. Electrons are the lowest energy level, most easily drawn by the core.
Danish physicist Neils Bohr called the failures, Rutherford atom through experiments on the hydrogen atom spectrum. His experiment managed to give an overview on the state of the electrons occupy the area around the atomic nucleus. Explanation of Bohr about the hydrogen atom involves a combination of the classical theory of Rutherford and the quantum theory of Planck, to say the four postulates, as follows:
1. There are only a certain set of orbits that are allowed for an electron in a hydrogen atom. Orbit is known as the stationary state of motion (settled) electron and a circular path around the nucleus.
2. As long as the electrons are in a stationary orbit, the electron energy anyway so there is no energy in the form of radiation emitted or absorbed.
3. Electrons can only move from one stationary orbit to another stationary trajectory. In this transition, a certain amount of energy involved, the amount in accordance with Planck equation, ΔE = hv.
4. Stationary trajectory is allowed to have the scale with certain properties, especially property called angular momentum. The magnitude of the angular momentum is a multiple of h/2Π or nh/2Π, where n is an integer and h Planck constant.
According to the Bohr model of the atom, the electrons around the nucleus in certain paths called electron shells or energy levels. The lowest energy level is the electron shell which is located in, getting out of her skin and the greater the number the higher the energy level.

Weaknesses:
This atomic model can not explain the spectrum of colors from many electron atoms.
5. Modern Atomic Theory
Atomic model of quantum mechanics developed by Erwin Schrodinger (1926). Before Erwin Schrodinger, an expert from the German Werner Heisenberg developed the theory of quantum mechanics known as the uncertainty principle is "not possible to set the position and momentum of an object carefully at the same time, which can determined is the probability of finding the electron at a certain distance from the nucleus. "
Region of space around the nucleus with a probability to get the so-called orbital electrons. The shape and orbital energy levels formulated by Erwin Schrodinger Schrodinger.Erwin solve an equation to obtain the wave function to describe the discovery of a possible limit of the electron in three dimensions.
Model of the atom with the orbital trajectories of electrons is called a model of a modern atom or atomic model of quantum mechanics that applies to this, as shown in the picture below.
Shows the electron cloud around the nucleus where the probability of an electron. Orbital describes the energy levels of electrons. Orbitals with the same energy level or nearly the same to form sub shell. Some sub leather combine to make such kulit.Dengan skin consists of several sub-skin and consists of several orbital subshell. Although the skin is the same position but not necessarily the same orbital position.
Characteristic atomic model of wave mechanics
1. The movement of electrons have wave properties, so the trajectory (orbit) is not stationary as the Bohr model, but following the completion of the square of the wave functions called orbitals (three-dimensional shape darikebolehjadian greatest discovery of the electron in the particular circumstances of an atom)
2. The shape and size of the orbital depends on the price of the three quantum numbers. (The electrons occupy orbital quantum numbers are expressed in)
3. The position of the electron from the nucleus as far as 0.529 Armstrong H according to Bohr rather than anything concrete, but it is probable the discovery of the electron greatest opportunities.


C. QUANTUM NUMBERS
To determine the position of an electron in an atom, used 4
quantum numbers.
1. The principal quantum number (n): realizing the electron trajectories in
atom.
n has a price of 1, 2, 3, .....
- N = 1 corresponds to the K shell
- N = 2 correspond to the L shell
- N = 3 corresponds to the skin M
- And so on
Each skin or any number of energy levels occupied by electrons.
The number of electrons that can occupy maksimmm energy levels
must satisfy the Pauli formula = 2N2.
Example:
skin-to-4 (n = 4) can be occupied by a maximum of electrons = 2 x 42 = 32
electron
2. Azimuthal quantum number (l): indicate sub skin where
electrons that move also shows a sub-skin
compilers of the skin.
Azimuthal quantum number have prices from 0 to (n-
1).
n = 1; l = 0; corresponding K shell
n = 2, l = 0, 1; corresponding L shell
n = 3; l = 0, 1, 2; appropriate skin M
n = 4; l = 0, 1, 2, 3; appropriate skin N
and so on
Sub leather prices vary is given a special name:
l = 0; fit leather sub s (s = sharp)
l = 1; fit leather sub p (p = principle)
l = 2; fit leather sub d (d = diffuse)
l = 3; fit leather sub f (f = fundamental)
3. Magnetic quantum number (m): realizing the presence of one or
several levels of energy in a sub shell. Quantum numbers
magnetic (m) has a price (-l) to price (+ l).
For:
l = 0 (sub leather s), price m = 0 (having 1 orbital)
l = 1 (p sub shell), price m = -1, O, +1 (have 3 orbitals)
l = 2 (sub skin d), price m = -2, -1, O, +1, +2 (have 5 orbitals)
l = 3 (f sub shell), price m = -3, -2, O, +1, +2, +3 (have 7
orbital)
4. Spin quantum number (s): indicates the direction of rotation of the electron
on its axis.
In one orbital, maximum of 2 electrons can circulate and second
This electron spins through the axis in the opposite direction, and
each one is priced spin +1 / 2 or -1 / 2.
Question:
How the four states of the electron quantum numbers 3S1?
Answer:
The four quantum numbers of the electron position can 3S1
expressed as,
n = 3; l = 0; m = 0; s = +1 / 2, or -1 / 2
D. ELECTRON CONFIGURATION
In every atom orbitals are available, but not necessarily
all orbital is filled. How is the electron charge
these orbitals?
Completion of electrons in the orbitals satisfy some rules.
among other things:
1. Aufbau principle: electrons fill orbitals starting with
the lowest energy level and beyond.
Orbital who meet the low energy levels is 1s
followed by 2s, 2p, 3s, 3p, and on and on
made easier following diagram:
Examples of filling electrons in orbitals several elements:
Atom H: has 1 electron, configuration 1s1
Atom C: has 6 electrons, the configuration 1s2 2s2 2P2
Atom C: has 19 electrons, the configuration 1s2 2s2 2P6 3S2 3P6
4S1
2. Pauli principle: not possible in the atom there are two electrons
with the same four quantum numbers.
This means, if there are two electrons that have a number
principal quantum, and magnetic azimuth of the same, then the number
quantum spins must be opposite.
3. Principle Hund: for filling electrons in orbitals in a sub
Skin is that the electrons do not form pairs of electrons
before each filled with an electron orbital.
Example:
- Atom C with an atomic number of 6, meaning it has 6 electrons and how
Charging orbitals are:
Based on the principle Hund, the first electron from 2s trajectory will
move to track 2pz, so now there are 4 electrons
pairs. Therefore, for all orbital is full, then the atom
carbon bonded to elements that can give 4 electrons.
So that in nature there is a compound CH4 or CCl4, but there is no
CCl3 compound or CCL5.

ENTHALPY

Enthalpy (H) is the amount of energy that the system at a constant pressure. Enthalpy (H) is defined as the amount of energy contained in the system (E) and work (W).
H = E + W
with:
W = P × V
E = energy (joules)
W = work system (joules)
V = volume (liters)
P = pressure (atm)
The law of conservation of energy explains that energy can not be created and can not be destroyed, but can only be converted from one form of energy into another form of energy. Energy value of the material can not be measured, which can be measured is the change in energy (ΔE). Similarly, the enthalpy, enthalpy can not be measured, we can only measure changes in enthalpy (ΔH).
ΔH = Hp - Hr
with:
ΔH = change in enthalpy
Hp = enthalpy of products
Hr = enthalpy of the reactants or reagents
a. If the product H> H reactants, then ΔH is positive, it means that the absorption of heat from the environment to the system.
b. When the reactant H> H products, then ΔH are negative, meaning the release of heat from the system to the environment.



Mathematically, enthalpy change (ΔH) can be derived as follows.
H = E + W (1)
At constant pressure:
ΔH = ΔE + PΔV (2)
ΔE = q + W (3)
Wsistem =-PV (4)
Substitution of equation (3) and (4) in equation (2):
H = (q + W) + PΔV
H = (q - PΔV) + PΔV
H = q
Thus, at a constant pressure, the change in enthalpy (ΔH) is equal to the heat (q) absorbed or released (James E. Brady, 1990).
Various kinds of chemical reactions based on the heat released / absorbed heat (Martin S. Silberberg, 2000):
a. Chemical reactions that require or absorb heat are called endothermic reactions.
example:
Termination reaction bonding in the molecule H2 elements are:
H2 → 2 H + a kJ ΔH =
Endothermic reaction with ΔH is positive (+).
b. The chemical reaction that liberates heat is called an exothermic reaction.
example:
Bond formation reactions at the molecular elements of H2 are:
2H → H2 kJ ΔH =-a
Exothermic reaction with ΔH marked (-).
Diagram enthalpy (energy level diagram)


Types of Enthalpy
 
1. Enthalpy of Formation
Enthalpy change for the formation of one mole of a substance directly from its elements called molar enthalpy of formation or the enthalpy of formation. If the measurement is made at the standard state (298 K, 1 atm) and all of its elements in the form of the standard, the enthalpy change is called the standard enthalpy of formation (ΔHf 0). Enthalpy of formation is expressed in kJ per mole (kJ mol -1).

So that there is uniformity, then it should set the standard state, the temperature 25 0 C and a pressure of 1 atm. Thus thermochemical calculations based on the state standards.

In general, in thermochemical equation stated:

AB + CD ----> AC + BD Δ H0 = x kJ / mol

Δ H0 is the epitome of the enthalpy change in circumstances. What is meant by the standard form of an element is the most stable form of the element at standard conditions (298 K, 1 atm).

Example: enthalpy of formation of ethanol (C2H5OH) (l) is -277.7 kJ per mole. This means: the formation of 1 mole (46 grams) of ethanol from elements in standard form, the carbon (graphite), hydrogen gas and oxygen gas, measured at 298 K, 1 atm 277.7 kJ released by termokimianya equation is :
2 C (s, graphite) + 3H2 (g) + ½ O2 (g) -> C2 H5 OH (l) ΔH = -277.7 kJ

Value of enthalpy of formation of various substances and the formation reaction thermochemical equations given in Table 2 below.

Table 2. Value of the enthalpy of formation of various substances and thermochemical reaction equation formation

2. Enthalpy of Combustion

The reaction of a substance with oxygen reaction called combustion. Substances that are combustible elements carbon, hydrogen, sulfur, and various compounds of these elements. Said to be perfect if the combustion of carbon (c) burned to CO2, hydrogen (H) burned into H2O, sulfur (S) burned to SO2.

Enthalpy change for the combustion of 1 mol of a substance is measured at 298 K, 1 atm is called the standard enthalpy of combustion (standard enthalpy of combustion), which is expressed by ΔHc0. Enthalpy of combustion is also expressed in kJ mol -1.

Price enthalpy of combustion of various substances at 298 K, 1 atm are given in Table 3 below.

Table 3. Enthalpy of combustion of various substances at 298 K, 1 atm

Burning gasoline is an exothermic process. If gasoline is considered consisting of isooctane, C8H18 (a component of gasoline) determine the amount of heat released in the combustion of 1 liter of gasoline. Given the enthalpy of combustion of isooctane = -5460 kJ mol-1 and the density isooktan = 0.7 kg L -1 (H = 1 and C = 12).

Answer:
Enthalpy of combustion of isooctane is - 5460 kJ mol-1. The mass of 1 liter of gasoline = 1 liter x 0.7 kg L-1 = 0.7 kg = 700 grams. Isooctane mole = 700 grams gram/114 mol-1 = 6.14 mol. So the heat is released in the combustion of 1 liter of gasoline is: 6.14 x 5460 kJ mol = 33524.4 kJ mol -1.

3. Enthalpy of Decomposition
Decomposition reaction is the opposite of a reaction formation. Therefore, in accordance with the principle of conservation of energy, equal to the value of the enthalpy of decomposition enthalpy of formation, but opposite sign.

Example:

Known ΔHf 0 H2O (l) = -286 kJ mol -1, the enthalpy of decomposition of H2O (l) into hydrogen gas and oxygen gas is + 286 kJ mol-1

H2O (l) -> H2 (g) + ½ O2 (g) ΔH = + 286 kJ

Fundamental laws of chemistry and chemical calculations (stoichiometry)

The term stoichiometry is derived from the Greek meaning stoicheon element and metron meaning measure. Thus, the stoichiometry is the study of the quantitative relationship between reactants and products in the reaction. Stoichiometry can also be said as a matter of chemistry.

In general, a chemical reaction takes place in solution. Before you reacting solution, of course you would calculate in advance how many agents will be treated and how much substance to be produced. In the chemistry that is studied in solution stoichiometry.To understand the concept of stoichiometry of the solution, it must first understand the types of reactions in an electrolyte solution, the sense of concentration, mole concept, and the equation.A. Reactions in Solution ElectrolytesDo you still remember about a solution that can conduct electric current? Called the solution is the solution? The reaction taking place in the solution is the ionization reaction. The solution is an electrolyte solution. Electrolyte solutions are classified into two kinds of weak electrolyte solutions and strong electrolyte solutions.The reaction between the ions in the electrolyte solution can generate covalent compounds, sludge, gas, or discoloration of the solution.1. Acid base neutralization reactionThe reaction between acid and alkaline compounds can produce mineral salts and water

                                    

                                   acid  + bases ↔ salts + water 

Example:KOH (aq) + HCl (aq) KCl (aq) + H2O (1)Mg (OH) 2 (aq) + H2SO4 (aq) MgSO4 + 2 H2O (1)The reaction between acids and bases commonly called neutralization reaction. However, not all salt produced from this reaction is neutral. There are salts that have acidic or alkaline properties. This depends on a strong or weak acids and bases react to form it.Strong acid + strong base → salt neutralStrong acid + base → salt weakly acidicweak acid + strong base → salt is alkalineThe concentration of acid or base solution can be determined based on the reactions that occur in the solution. This method is known as the acid-base titration. Titration experiments performed by adding acid or base solution of known concentration (a standard solution) to a solution of acid or base to known concentration. The addition continued until the equivalent point is reached, the point at which acids and bases react right out. If the volume of the standard solution and the sample solution is known, the concentration of the sample solution can be determined.

2. Oxide Reaction with Acid TongueAlkaline oxides react with acids to form salts and waterOxides of acid + base → salt + H2OExample:K2O (s) + H2SO4 (aq) → K2SO4 (aq) + H2O (1)3. Acid Oxide Reaction with BasesThe reaction between oxides asama with bases to form salts and waterOxide acid + base → salt + H2OExample

 

4. Precipitation ReactionSome of cations and anions in the electrolyte solution to form a solution of poorly soluble in waterExample:

 

5. Reactions that Produce GasReaction abebrapa acid solution with metal to produce hydrogen gas.Metal oxide + acid → salt + H2Example:

 

Metal can react with acidic metal on the left side of hydrogen atoms on the following voltaic series:

B. Stoichiometric solutionMost chemical reactions can take place more quickly if the reactants in solution form. Why is that? What distinguishes the chemical reactions in solution (homogeneous mixture) with a heterogeneous mixture? Before discussion of the stoichiometric solution then we will discuss first about the concentration of the solution.

1. Concentrationa. Definition of ConcentrationConcentration is a general term to indicate the number of parts of the solute and solvent present in the solution. Concentration can be expressed quantitatively as well as qualitatively. For a qualitative measure, the concentration of the solution expressed in terms of a concentrated solution (concentrated) and liquid (dilute). The term second states the relative solute and solvent in the solution. Concentrated solution means that a relatively large amount of solute, while the mean number of aqueous solutes are relatively few. Typically, the terms concentrated and dilute concentrations used to compare two or more solutions.In a quantitative measure, the concentration of the solution expressed in g / mL (the same as the units for density). However, the stoichiometry calculations grams replaced with units of moles to obtain units of mol / L. Concentration in mol / L or mmol / mL known as molarity or molar concentration.b. MolarityMolarity or kernolaran stating the number of moles of solute (n) in one liter of solution (L) or millimoles of solute (n) in any one milliliter of solution (mL).

 

Description: W = weight of substance (g)Mr = period of relative molecular substancesV = volume of solution (mL)A solution can be prepared by dissolving the solute from the dilute solution murniatau pekatnya: To be more clear, consider the following example:1) Determination of Molarity by Dilution MethodIf we want to make a 250 mL solution of 0.25 M K2CrO4 from the crystalline form, the way is to calculate the mass of the substance to be dissolved.mol K2CrO4 = 250 mL x 0.25 M= 0.0625 molg K2CrO4 = 0.0625 mol x 194 g / mol= 12.125 gSo, the thing to do is dissolve 12.125 g K2CrO4 crystals into 250 mL of water2) Determination of Molarity by Dilution MethodIf the solution above will be converted into 0.01 M K2CrO4 concentration, the way is by way of dilution. In dilution we will change the volume and kemolaran solution, but does not change the number of moles of solute.

nl = n2 → n = MV↓M1 V1 = M2V2Description:M1 = concentration before dilutionV1 = volume before dilutionM2 = concentration after dilutionV2 = volume after dilutionFor the above example, we can take 10 mL of 0.25 M K2CrO4 After that, the dilution calculation:M1V1 = M2V20.25 M x 10ml = 0.01 MxV2

= 250 mLSo, the thing to do is dilute 10 mL of 0.25 M K2CrO4 up the volume to 250 mL.If the two types of solutions are mixed and the number of moles of solute change (n1 does not equal n2), then the moles of the substance after mixed depending on the numbernl and n2, while the volume of the solution to V1 + V2.

2. Chemical Calculationsa. Mol and Reaction EquationsIn class X you have learned about the concept of the mole. On this subject, you will learn the concept of the mole and an integrated equation. We have discovered that one mole of a substance contains 6.02 x 1023 particles of the compound. If applied to an atom or molecule, then:1 mole = 6.02 x 1023 atoms / moleculesTo remind the relationship between the concept of moles by the number of particles, the mass of the atom / molecule, the standard volume and molarity, note the diagram "Mol Bridge" below!

The chart above shows that the mole ¬ able to bridge the various parameters that allow us to understand a chemical reaction.On the chart, it was shown that all paths leading to the mole using a "division", while the path out of the mole using the "multiplication", except for the molarity (M).For example, consider the following reaction?H2 (g) + O2 (g) - H2O (g)The reaction shows that the number of oxygen atoms in the reactants are two pieces, while the amount of oxygen in the product there is a fruit. This is different from the H atom is the same. Therefore, the reaction must be synchronized.Equalization of the reaction can be done by making the coefficient of O2 = ½ so that by the following equation.H2 (g) + ½ O2 (g) - H2O (g)In the above reaction the number of atoms on the reactant O to H is equivalent to the number of atoms of O and H on the product. Fractional number in the equation can be removed by multiplying two coefficients of all reactions.2H2 (g) + O2 (g) 2H2O (g)The above equation shows that the reaction coefficient respectively for H2, 02, and H2O is 2, 1, and 2. In the calculation of chemical reaction coefficient represents the ratio of moles of the substance in the reactants and products of a reaction. That is, the mole ratio in the reaction above, between H2, 02, and H2O is 2: 1: 2.Consider the illustration below!
2H2 (g) + O2 (g) ---------------- 2H2O (g)

Mole ratio of 2: 1: 2

Another example is the combustion of methane gas in the air.------------------------ methane + oxygen carbon dioxide + waterCH4 + 202 ---------- ------------- CO2 + 2H20

Equation shows that 1 mole of CH4 reacts with 2 moles of O2 to produce 1 mole of CO2 and 2 moles of H2O.From the equation we can say that:The number of moles of H2O produced = 2The number of moles of CH4 in action 1This comparison can be used to calculate the mass of water produced when burning a certain amount of methane in the air.b. Reaction Mass Calculation AgentIf you want to do a reaction in the laboratory, you would measure the reagents in units of grams or liters before rnereaksikannya. Therefore, work in the laboratory will always be associated with the mass calculation.Determination of the number of products and reactants involved in the reaction must be calculated in units of mol. That is, the unit-¬ units known to be changed into the form of a mole. The method is often used in chemical calculations is called the method of approach mol.Step-by-step method mole approach can be seen in the following steps.1. Give the equation of the matter in question, and then synchronized.2. Change all the known units of each substance into moles3. Use coefficients to balance the number of moles of reaction reactant substances and products.4. Change units of moles of substance in question into the unit in question.
C. Neutralization Reaction1. Titration ProcessOne application is the solution stoichiometry calculations find molarity or concentration of a substance in the sample solution through a process called volumetric analysis. Volumetric analysis is a quantitative chemical analysis is done by measuring the volume of a standard solution appropriate to react (react perfectly) with the solution being analyzed. For example, to search for the solution molarity Z, then Z is added to a solution of the standard solution resulting in complete reaction between the solution Z with standar.Larutan standard solution is a solution of the concentration or molarity standard pasti.Larutan have known there are 2 kinds, namely primary standard solution and secondary standard solution. Primary standard solution is a solution of the following standards are made, can be directly used to add to the concentration of the solution to be sought. Secondary standard solution standard solution after it is created can not be directly used, but must be checked again molarity concentration or by adding a solution of a primary standard. The process of checking the secondary standard solution with a solution of a primary standard is called standardization.The process of adding a standard solution to a solution of Z (which will be determined concentration) is called titration. This made the process of adding little by little (drop by drop) using an instrument called burette. Every single drop of standard solution out of the burette volume ± 20 mL. Substance to be titrated is placed in erlenmeyer.At the completion of the reaction between a standard solution with a solution called endpoint analyzed. At this point reached, the titration is stopped.In volumetric analysis, the reaction between the standard solution with the solution being analyzed must meet several requirements, among others:1. Chemical reactions that occur should be simple and straightforward equation written.2. Reactions should be able to run fast. Last drop of standard solution must be able to demonstrate complete reaction. If not, there will be mistakes titration.3. At the completion of the reaction (endpoint) is reached, there must of change in physical or chemical properties that can be observed or indication of changes can be detected by adding a solution of the indicator into the solution to be titrated or can be caused by the color of the solution own standards.For example, the neutralization reaction of NaOH solution with HC1 solution. Neither solution of NaOH or HC1 is the clear solution. The results of the reaction (NaCl and H20), is also the clear, so the endpoint can not be observed. To that end, in the titrated solution (NaOH), was added a solution of indicators, such as phenolphthalein indicator, abbreviated (pp) is an indicator that in alkaline solution gives red color in acidic solution is colorless. The addition of these indicators using a Pasteur pipette. The number of indicator solution were added just one or two drops. Titration of NaOH with HC1 using pp indicators and endpoint is reached when the last drop addition of HCl solution gives discoloration.
2. Titration Acids BasesOne application of the concept of neutralization reaction is the acid-base titration. In acid-base titration, the value of the equilibrium constant of ionization used as a benchmark for determining the pH of the solution while achieving equivalent point. Equivalent point or end point is when the theoretical amount of acid or base added exactly equivalent stoichiometric with the amount of base or acid in the solution • analyzed.The formula can be used to determine the concentration of the sample solution is as follows:Sample mol = standard mol M sample V sample = M standard Vstandard