Some Relevant Equations
Some Relevant Equations for chemistry
some important chemistry equations
energy equation
free energy equation
gas laws formulas
beer-lambert law
3.8.14
28.3.14
Complex Ion Definition
Complex Ion Definition
An introduction to complex ions definition with an explanation of what ligands are and how they bond to the central metal ion.
What is a complex metal ion?
A complex ion has a metal ion at its centre with a number of other molecules or ions surrounding it. These can be considered to be attached to the central ion by co-ordinate bonds. (In some cases, the bonding is actually more complicated than that.)
Complex Ion Definition: Complex ions are ions with a central metal ion bonded to one or more molecules or ions.
Examples of Complex Ion formation:
The copper ammine ion complex
Cu2+ + 6NH3 -------> [ Cu(NH3)6]2+ is a complex ion.
27.2.14
determination of barium direct titration with methyl thymol blue
Determination of Barium: Direct Titration using Methyl Thymol Blue as indicator
Can you determine the barium ion by EDTA titration?
determine the concentration of barium ions in a solution by direct titration with methyl thymol blue
you can determine the barium ion in sulfate by determination of barium sulfate, determination of barium sulfate, determination of barium in water and determination of barium in drinking water by this method
Also, you can see: Determine of Copper (ii) ions by EDTA titration or Determination of Mn by titration with EDTA
Also, you can see: Determine of Copper (ii) ions by EDTA titration or Determination of Mn by titration with EDTA
PRINCIPLE:
Complexometric titration of Barium(II) ions directly with EDTA can only be
effected in alkaline solution since the complex is broken down in acidic media. Methyl
Thymol Blue is used as indicator which is gray when it is free (H4ln) and blue when
complexed with Barium.
REAGENTS:
1- Barium ions solution (analyte)
2- 1M sodium hydroxide solution (pH 12)
3- Methyl Thymol Blue indicator
4- 0.01 M EDTA solution
PROCEDURE:
1- Pipette 25.0 mL of Barium ions solution into a 250.0 mL and dilute to about
100mL with de-ionised water. Adjust the pH of the solution to 12 by the
addition of 3-6 mL of 1M sodium hydroxide solution.
2- Add 50 mg of methyl thymol blue indicator.
3- Titrate with 0.01 M EDTA until the color changes from blue to gray. Record
the used volume (as V EDTA).
4- Repeat the titration twice
Atomic weight of Barium = 137.34 g/mol
16.2.14
Principles of Colour Chemistry
Basis for colour
Unlike most organic compounds, dyes possess colour because they:
1) Absorb light in the visible spectrum (400–700 nm),
2) Have at least one chromophore (colour-bearing group),
3) Have a conjugated system, i.e. a structure with alternating double and single bonds.
4) Exhibit resonance of electrons, which is a stabilizing force in organic compounds .
When any one of these features is lacking from the molecular structure the colour is lost. In addition to chromophores, most dyes also contain groups known as auxochromes (colour helpers), examples of which are carboxylic acid, sulfonic acid, amino, and hydroxyl groups. While these are not responsible for colour, their presence can shift the colour of a colourant and they are most often used to influence dye solubility. Figure 1 shows the relationships between wavelength of visible and colour absorbed/observed.
Figure 1: . Wavelength of light absorption versus colour in organic dyes
Determination of Mn by titration with EDTA
How can you determine the concentration of Manganese Mn ions in solution?
you can determine Mn+2 by EDTA (Ethylene diamine tetra acetic acid) titration
Determination of Manganese(ii) ions by Direct EDTA Titration using Eriochrome Black T as indicator
Manganese Mn
Atomic Weight 54.938049
Density 7.47 g/cm3
Melting Point 1246 °C
Boiling Point 2061 °C
PRINCIPLE:
Manganese ions (Mn+2) concentration in a sample can be determined quantitatively by
complexometric direct titration with EDTA at pH 10. Eriochrome black T is used as an
indicator; it is Blue when it is free (Hln2-) and wine-red when complexed with Zinc.
Like all manganese(II) containing species, it readily undergoes oxidation in alkaline
media to form products of uncertain stoichiometry. For this reason, manganese (II) is
always titrated in the presence of a reducing agent such as ascorbic acid or hydroxylammonium
chloride.
REAGENTS:
1- Manganese ions solution (analyte)
2- Hydroxylammonium chloride or ascorbic acid
2- pH10 buffer solution
3- Eriochrome black T indicator
4- 0.01 M EDTA solution
m
PROCEDURE:
1- Pipette 25.0 mL of Manganese ion solution in a 250.0 mL conical flask and
dilute to about 100.0 mL with distilled water. Add 0.25 g hydroxylammonium
chloride or ascorbic acid [this is to prevent oxidation of Mn(II) ions].
2- Add 2‒3 mL of pH10 buffer solution and 30-40 mg of Eriochrome Black T
indicator.
3- Titrate with 0.01 M EDTA until the color changes from wine-red to pure
blue. Record the used volume (as V EDTA).
4- Repeat the titration twice.
Atomic weight of Manganese = 54.94 g/mol
REAGENTS:
1- Manganese ions solution (analyte)
2- Hydroxylammonium chloride or ascorbic acid
2- pH10 buffer solution
3- Eriochrome black T indicator
4- 0.01 M EDTA solution
m
PROCEDURE:
1- Pipette 25.0 mL of Manganese ion solution in a 250.0 mL conical flask and
dilute to about 100.0 mL with distilled water. Add 0.25 g hydroxylammonium
chloride or ascorbic acid [this is to prevent oxidation of Mn(II) ions].
2- Add 2‒3 mL of pH10 buffer solution and 30-40 mg of Eriochrome Black T
indicator.
3- Titrate with 0.01 M EDTA until the color changes from wine-red to pure
blue. Record the used volume (as V EDTA).
4- Repeat the titration twice.
Atomic weight of Manganese = 54.94 g/mol
15.2.14
Determine of Copper (ii) ions by EDTA titration
how can you determine of copper (ii) ion concentration ?
in this post we answer on this question by explain the method of EDTA titration that is used to determination of copper cu2+ by complexometric titration
+ions+by+EDTA+titration.jpg "in this post we answer on this question by explain the method of EDTA titration that is used to determination of copper cu2+ by complexometric titration")
Determination of Copper: Direct Titration using Murexide as indicator
PRINCIPLE:
Copper(II) ions can be determined quantitatively by complexometric direct
titration with EDTA in ammoniacal solution. The indicator used is Murexide indicator
which is purple when it is free (H4ln-) and yellow (green) when complexed with copper.
It should be noted that this method is only applicable to solutions containing up to
25 mg copper ions in l00mL of water; if the concentration of Cu2+ ions is too high, the
intense blue color of the copper(II) ammine complex masks the colour change at the end
point. The indicator solution must be freshly prepared. The copper-murexide complex is
pure yellow, but the color at the starting point of the titration is greenish depending on
the amount of copper present. The green is the mixture of yellow (indicator complex)
and blue (copper ions).
REAGENTS:
1- Copper(II) ions solution (analyte)
2- Ammonia solution (1:1) as a buffer pH <9
3- Murexide indicator
4- 0.01 M EDTA solution
PROCEDURE:
1- Pipette 25.0 mL of Copper ions solution into a 250.0 mL and add Add
ammonia solution drop-wise until the light blur precipitate first formed
dissolves to form a clear blue solution and dilute to about 100.0 mL with
distilled water.
2- Add 3 to 4 drops of Murixide indicator.
3- Titrate with 0.01 M EDTA until the color changes from yellow (green) to
purpule. Record the used volume (as VEDTA).
4- Repeat the titration twice.
Atomic weight of copper = 63.55 g/mol
14.2.14
determination of zinc ion by edta titration
How can you Determination of Zinc (Zn+2) in solution
Determination of Zinc ion by Direct Titration using Eriochrome Black T as indicator
PRINCIPLE :
Zinc content in a sample can be determined quantitatively by complexometric
direct titration with EDTA at pH 10. The effective formation constant of the Zn-EDTA
complex is ≥ 106 above pH 4. Eriochrome black T is used as an indicator; it is Blue when it
is free (Hln2-) and wine-red when complexed with Zinc.
Initially, when the pH of the medium maintained at pH 7‒11, the Zinc ions
combine with indicator molecules to form Zn-indicator complex which appear as a winered
color. Near the end point, EDTA breaks the Zn-indicator complexation, resulting in
the formation of Zn-EDTA complex. Hence at the end point, the liberated free indicator
yields a blue color to the solution.
REAGENTS :
1- Zinc ion solution (analyte)
2- pH10 buffer solution
3- Eriochrome black T indicator
4- 0.01 M EDTA solution
PROCEDURE:
1- Pipette 25.0 mL of Zinc ion solution into a 250.0 mL conical flask and dilute to
about 200.0 mL with distilled water
2- Add 1 to 2 mL of pH10 buffer and 3 to 4 drops of Eriochrome Black T indicator to
each.
3- Titrate with 0.01 M EDTA until the color changes from wine-red to pure blue.
Record the used volume (as VEDTA).
4- Repeat the titration twice.
Atomic weight of Zinc = 65.41 g/mol
-Complexometric Titration of Zn(II) with EDTA
-
10.2.14
Determination of Magnesium by Direct Titration using Eriochrome Black T as indicator
How can you Determine the Magnesium ion by complexometric titration
PRINCIPLE :
The concentration of Magnesium ions in a sample can be determined quantitatively by complexometric direct titration with EDTA. For Mg2+, the complexation reactions with Y4‒ and corresponding formation constants Kf are:
The large magnitude of this formation constant indicates that the above reactions will go to completion if the EDTA is present in its completely deprotonated form Y4‒. Furthermore, the great stability of the complex
would lead to a sharper end point. To ensure that the titrant is in its completely deprotonated Y4‒
form, pH value greater than 12 is necessary. Unfortunately, the precipitation of Mg2+ as Mg(OH)2 precludes
the titration at such high pH. Instead, the titration can be carried out at pH 10. At this pH, a portion of
the EDTA is in the HY3‒ form and the additional complexation reactions and conditional formation constants at this pH are:
As EDTA and its metal ion complexes are colorless, a metal ion indicator that undergoes a color change when transformed from the metal ion–bound to the unbound form is needed. Eriochrome black T is used as an indicator; it is Blue when it is free (Hln2-) and wine-red when complexed with magnesium. As the EDTA titrant is added to sample, free Mg2+ ions are captured first. After complexation of all the free ions, EDTA reacts with the small amount of bound metal ion–indicator complex. The metal ions are effectively removed from the indicator as EDTA binds more tightly to these ions. This victory in the competition for the metal ion is only possible because of the value of the formation constant for the Mg2+- Eriochrome black T complex,MgIn‒, is smaller than that for the Mg-EDTA complex, MgY2‒. The color change during titration:
REAGENTS:
1- Magnesium ion solution
2-pH10 buffer solution
3- Eriochrome black T indicator
4- 0.01 M EDTA solution
PROCEDURE :
1- Pipette 25.0 mL of Magnesium ion solution in a 250.0 mL conical flask and dilute to about 200.0 mL of distilled water
2- Add 1 to 2 mL of pH10 buffer and 3 to 4 drops of Eriochrome Black T indicator to each.
3- Titrate with 0.01 M EDTA until the color changes from wine-red topure blue. Record the used volume (as VEDTA).
4- Repeat the titration twice.
9.2.14
introduction about complexometric titration
Complexation reactions are widely used in analytical chemistry.
One of the first uses of these reactions was for titrating cations, the major topic of this work.
A complexometric titration is the one of titrimetric methods in which the reaction between
the analyte and titrant involves the formation of a complex.
a successful analytical method must meet the following requirements:
(i)
the
reaction must be sufficiently fast;
(ii)
it
should lead stoichiometrically to a single product ML without any intermediate
reactions or by-products;
(iii)
there
should be a large increase in free energy (see Gibbs Energy), so that the
reaction is effectively complete, that is, the stability constant; Kf
must be large;
(iv)
the
ligand L must be readily available and give stable standard solutions;
(v)
there
must be some simple means of monitoring the course of the reaction, that is,
for following changes in the concentration [M] or [ML].
These conditions are generally met if L is the conjugate base of an aminopolycarboxylic acid such as ethylenediaminetetraacetic acid (EDTA), which is known to form very stable 1:1 complexes with a large number of metals.
The earliest examples of metal–ligand complexation titrations are Liebig’s determinations, in the 1850s, of cyanide and chloride using, respectively, Ag+ and Hg2+ as the titrant. Practical analytical applications of com¬plexation titrimetry were developed after the introduction of amino carboxylic acids as multi-dentate ligands by Schwarzenbach in 1945.
The earliest examples of metal–ligand complexation titrations are Liebig’s determinations, in the 1850s, of cyanide and chloride using, respectively, Ag+ and Hg2+ as the titrant. Practical analytical applications of com¬plexation titrimetry were developed after the introduction of amino carboxylic acids as multi-dentate ligands by Schwarzenbach in 1945.
6.2.14
بالفيديو اسهل طريقة للبحث وتنزيل ابحاث الماجستير والدكتوراة مجانا scientific publications
الكثير من الباحثين والمهتمين بكتب وابحاث الماجستير والدكتوراة يجدون صعوبة شديدة حتى يجدوا ما يتوافق مع ابحاثهم العلمية , فمن الناس من يتجة الى جوجل ومنهم من يبحث عن ابحاث الماجستير والدكتوراة فى المكتبة ولكن هذا يتطلب جهد ووقت كبير فى عملية تجميع الابحاث والرسائل
بإمكانك تحميل اكثر من 20 مليون بحث
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افضل طريقة لتنزيل الابحاث العلمية والرسائل العلمية من الماجستير والدكتوراة مع افضل موقع للأبحاث العلمية
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بإمكانك تحميل اكثر من 20 مليون بحث
download over 20 million free science papers, patents, theses and posters
اليوم ااتى لكم بشرح بالفيديو يعرض فية كيفية البحث فى موقع ممتاز وتنزيل الابحاث ورسائل الماجستير والدكتوراة مجانا
افضل طريقة لتنزيل الابحاث العلمية والرسائل العلمية من الماجستير والدكتوراة مع افضل موقع للأبحاث العلمية
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