7 .- Methods for balancing or balancing chemical equations
1. Balancing equations by the method of Scoring
2. Balancing equations by the method of Redox
3. Balancing equations by the algebraic method
1. http://html.rincondelvago.com/balanceo-de-ecuaciones-quimicas.html
2. http://www.cespro.com/Materias/MatContenidos/Contquimica/QUIMICA_INORGANICA/reacciones_quimicas.htm
3. http://www.geocities.com/Colosseum/Loge/3802/balanceodeeecuaciones.html
8 .- Explain the process of each methods using two examples in each. Describe the necessary terminology.
1. SCORE OR INSPECTION METHOD
"This method is used for simple equations and involves placing coefficients to the left of each substance, to have the same number of atoms in both reactants and products.
EXAMPLE:
| N 2 | + | H 2 | → | NH 3 |
In this equation there are two nitrogen atoms in the reactants, therefore should be placed coefficient of 2 to NH 3 , so that in the products is the same number of atoms of that element.
| N 2 | + | H 2 | → | 2 NH 3 |
By placing this factor in the product have six atoms of hydrogen to balance them is to place a ratio of 3 to H 2 reactant:
| N 2 | + | H 2 | → | 2 NH 3 |
The equation has been balanced. The number of atoms of each element is the same in reactants and products. "
Balancing equations by the method of Redox
In a backlash if an element is oxidized, it must also be an element that is reduced. Remember that a reaction of oxide reduction is not nothing but a loss and gain of electrons, ie, release or absorption of energy (the presence of light, heat, electricity, etc.).
To balance a reaction this method, consider the following steps:
1) Determine the oxidation numbers of different compounds that exist in the equation.
to determine oxidation numbers of a substance shall be taken into account:
always exist in a formula in as many numbers of positive and negative oxidation
The Hydrogen almost always works with +1, to ecepcion hydrides hydrides where he works with -1
Oxygen almost always works with -2
Anything you are alone, not attached to another, has oxidation number 0
2) After determining the oxidation numbers is analyzed element by element, comparing the first member of the equation with the second, to see what chemical elements change their oxidation numbers
0 0 +3 -2
Fe + O2 Fe2O3
elements that change their oxidation number is the Iron and Oxygen, as the oxygen goes from 0 to -2 and 0 to +3 Fierro
3) comparing numbers items ranging in scale redox
0 0 +3 -2
Fe + O2 Fe2O3
The oxidized iron 3 and the oxygen reduced by 2
4) If the element is oxidized or reduced oxidation number 0, the numbers multiply oxidized or reduced by the subscript element has oxidation number 0
Fierro is oxidized in 3 x 1 = 3
Oxygen is reduced by 2 x 2 = 4
5) The numbers were crossed, ie the number of the element gets the oxide is reduced and vice versa
4Fe + 3O2 2Fe2O3
numbers finally obtained as coefficients in place of the equation that has more terms and from there continue to balance the equation by trial and error
Balancing equations by the algebraic method
This method is based on the application of algebra. To balance equations should consider the following points
1) Each formula of the equation is assigned a literal and reaction arrow equals sign. Example:
Fe + O2 Fe2O3
ABC
2) For each chemical element in the equation, we propose an algebraic equation
For Fierro A = 2C
For Oxygen 2B = 3C
3) This method allows you to assign a value (the one you want) to the letter that appears in most of algebraic equations In this case the C
So if C = 2
Solving the first algebraic equation, we have:
2B = 3C
2B = 3 (2)
B = 6 / 2
B = 3
The results obtained by this method are algebraic
A = 4
B = 3
C = 2
write These values \u200b\u200bare coefficients in the formulas as they relate to each literal of the chemical equation, the equation is balanced
4Fe + 3O2 2 Fe2O3
1. http://www.cespro.com/Materias/MatContenidos/Contquimica/
2. http://html.rincondelvago.com/balanceo-de-ecuaciones-quimicas.html
9 .- Write 5 examples of equations for each of the methods for balancing chemical equations.
Scoring Method
- Examples:
1. H2SO4 -> H2O + SO3
2. HNO3 -> N2O5 + H2O
3. Fe + H Br -> Fe + H2 Br3
4. Ba + H2SO4 -> BaSO4 + H2
5. Na + H3PO4 -> Na 3 PO 4 + H2
Redox method for you:
- Examples:
KClO3 KCl + O2
+1 +5 -2 +1 -1 0
KClO3
KCl + O2 Cl reduces 6 x 1 = 6
or oxide in 2 x 1 = 2
2KClO3 2KCl + Cu + HNO3
6O2 NO2 + H2O + Cu (NO3) 2
0 +1 +5 -2 +4 -2 +2 -2 +2 +5 -2
Cu + HNO3 NO2 + H2O + Cu (NO3) 2 Cu
oxidized in 2 x 1 = 2
N reduced by 1 x 1 = 1
Cu + 2NO2 + H2O HNO3 + Cu (NO3) 2
4HNO3 Cu + 2NO2 + 2H2O + Cu (NO3) 2
Algebraic meted By:
- Examples
HCl KMnO4 + KCl + MnCl2 + H2O + Cl2
ABCDEF A = \u200b\u200b2E
Cl) A = C +
2F 2D + B = C
Mn) B = D
O) 4B = E
If B = 2
4B = E 4 (2) = E
E = 8 B = C
C = 2 B =
D = 2 D
A = 2E A = 2 (8)
A = 16
A = C + 2D + 2F
16 = 2 + 2 (2) + 2F
F = 10 / 2 F = 5
2KCl 2KmNO4 16HCl + + + 8H2O + 5Cl2 2MnCl2
10. Find out about how they are constructed minimum plating equipment, materials needed and everything related to your application
1º Put water up to 3 / 4 parts of the glass bowl and add copper sulfate to saturation (ie until it is dissolved). 3 º Connect the black wire to the negative terminal of the battery and the red with the positive and make the elements iron and copper in the basin.
2 º
Add the black wire one of the alligator clips and attach the element iron. Perform the same operation with the red wire, which will hold the copper plate.
4 º
As the current flows can be observed as copper and iron corrode will "copper"
http://www.practiciencia.com.ar/cfisicas/quimica/galvano/
11. Write a vocabulary where the definitions are of any new word you found during the investigation.
Oxidation: refers to the average reaction where an atom or group of atoms lose
Reduction : refers to the average reaction where an atom or group of atoms gain
Oxidizing Agent: is the substance that is reduced (gains e-) causing oxidation.
Reducing Agent: is the substance that is oxidized (loses e-) leading to the reduction.
Anodes: m. Chem. Positive electrode.
Kinetics: Party of chemistry that studies the mechanical properties of chemical reactions.
Electrolysis: f. Chem. Decomposition of a body produced by electricity.
Endothermic: f. Chem. called endothermic reaction is any chemical reaction that absorbs heat.
stoichiometric : m. Chem. Part of the chemical responsible for the quantitative study es6tudio of reagents and products in a chemical reaction .
Exothermic: exothermic reaction is called to any chemical reaction that releases heat. Occurs mainly in the oxidation reactions. When this is severe can lead to fire.
Galvanizing: Apply a layer of metal on metal, using the effect galvanism.
reactant: m. Chem. Initial substances are present in a chemical reaction.
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