Stoichiometric
A. Tata Compound Name
1. Nomenclature of Inorganic CompoundsThe nomenclature of inorganic compounds are generally grouped into two, namely:a. Naming Binary CompoundsBinary compound is a compound composed of two types of elements.• Binary Ionic CompoundsBinary compound of a metal and a metal ion compounds. Ionic
compound consisting of positive ions (cations) which is a metal ion and
a negative ion (anion) which is a non-metallic ions.Table cations and anions of Binary Compounds Metals and non-metalsType Ion Ion Formula Formula Ion Name Ion Name IonCations Na + Fe3 + Sodium Iron (III)Potassium K + Cu + Copper (I)Magnesium Mg 2 + Cu 2 + Copper (II)Ca2 + Calcium Co2 + cobalt (II)Ba2 + + CO3 Barium Cobalt (III)Al3 + + SN2 Aluminium Tin (II)Ni2 + Nickel + SN4 Tin (IV)Zn2 + Pb2 + Zinc Lead (II)Pb4 Ag + Silver + Lead (IV)F-Fluoride anion H-HydrideCl-Chloride-Oxide O2Br-Bromide S2-sulfideI-N3-Nitride IodidesMetal
and non-metal binary compounds are neutral (uncharged), meaning that
the charge of cations and anions are equal or the charge on the cation
and anion in a compound is zero.In General: Ay +AxByBx-Ay + ions bind to the ion Bx AxBy-forming ionic compounds, the ion charge an index Ay + Bx-B and charge an index A.Writing rules and naming binary compounds and metals and non-metals are as follows:1) Writing formulas of compounds, cations cations in front and behind.2)
The metal ion has only one charge (electric charge), the naming of
compounds is the name of the metal ion in the front and the name behind
non-metallic ions. Metal whice like this is an alkali metal (IA), alkaline earth (IIA), and aluminum.3)
metal ions have multiple charges (electric charge), Naming compounds is
the name on the front of the metal ions with the ionic charge by
writing to the Roman numerals in parentheses, while the name of the
non-metallic ions behind.The compound belongs to the binary compounds of metals and non-metals, namely;1) Compound SaltsSalt compound obtained from the reaction between an acid with a base. The salt compound is formulated as follows.Salt compound is formed from metal ions and ion rest Ly + Ax acid-forming salts LxAy2) Oxidation of Metals (Oxidation Basa)Oxidation of metal is an alkaline forming in water oxidation. Oxidation of metal formula is as follows.The compound is formed from the oxidation of metal ions and metal ions Ox + Ly-forming metal oxide compounds.Table Name Oxidation Metals and Basa are FormedOxidation of Metals Oxidation name formed Metal BasesLithium oxide Li2O LiOHSodium oxide Na2O NaOHK2O potassium oxide KOHMagnesium oxide MgO Mg (OH) 2Strontium Oxide SrO Sr (OH) 2Barium oxide BaO Ba (OH) 2Aluminium oxide Al2O3 Al (OH) 3Cr2O3 Chromium (III) oxide Cr (OH) 3FeO Iron (II) oxide Fe (OH) 2Fe2O3 Iron (III) oxide Fe (OH) 3• non-metallic and non-metallic Binary Compounds (Covalent Compounds)Non-metallic with non-metallic compounds are binary covalent compounds. The smallest particle of a compound is a molecule. Covalent compounds can be formulated as follows.
A and B are non-metals. Elements of A are more likely to positively charged and the element B is more likely to negatively charged. The letter x is the index of the element of A, ie the number of atoms making up the molecules A AxBy. The letter y is the index of the element of B, B is the number of atoms making up the molecules AxBy. Formation of molecular compounds AxBy by sharing electron pairs.Writing and naming rules binary compounds between non-metallic and non-metallic (covalent compounds) are as follows.1)
For the positively charged atoms that tend to be written on the front
and the negatively charged atoms that tend to be written on the back.Example: N to O, the formula N2O compounds not On22)
For non-metallic compound which forms only one compound, its name is
the name of the second element and the second element are given the
suffix ida.Example:HCL: Hydrogen ChlorideH2S: Hydrogen Sulfide3)
For non-metallic compounds that can form two or more compounds, naming
naming as above, but each is given a prefix that states the number of
atoms of each element and ending with ida. Prefix is a Greek index numbers. Prefix used is as follows.1 = mono2 = on3 = tri4 = tetra5 = penta6 = hex7 = hepta8 = octaExample:N2O: Nitrous monoxideNO: Nitrogen monoxideNO2: nitrogen dioxideNote:The prefix mono is not used on the front element that lies ahead, such as NO2 do not need to read mononitrogen dioxide.4) The compound is a common and well-known not following the rules above.Example:H2O: WaterNH3: AmmoniaBinary covalent compounds composed of amino compounds and oxides of non-metals monoksi.1) Acid Compounds NonoksiAccording to Arrhenius, an acid is a substance that can release H + ions in water. This is called the amino acid nonoksi Because it does not contain an acidic oxide. In contrast, amino acid-containing oxide is an acidic oxide.Naming nonoksi acid compound can be written as follows.
Example:HF: florida acidHCl: hydrochloric acidHbr: hydrogen bromideHI: Acid IonidaNote:HCN is not a binary compound, but its name as nonoksi acid. Naming HCN is hydrogen cyanide.2) Oxides of non-metalsOxide is a compound of an element with oxygen. Oxides of non-metals non-metals are oxides which, when dissolved in water to form acidic compounds. Non-metallic oxide is also called acid oxide. However, not all non-metallic oxides including acidic oxide. The general formula is as follows-metallic oxides.
The naming of non-metallic oxide has been described in naming non-metallic and non-metallic binary compounds.Major non-metallic non-metallic oxide Acid oxide formedSulfur dioxide SO2 H2SO3Sulfur trioxide SO3 H2SO4Dinitrogen trioxide N2O3 HNO2HNO3 N2O5 dinitrogen pentaoksidaDifosfor trioxide H3PO3 P2O3Difosfor pentaoksida H3PO4 P2O5b. Naming polyatomic compoundsPolyatomic compounds are compounds composed by more than two types of elements. Polyatomic compound consists of:• Ionic compounds polyatomicPolyatomic ionic compounds are compounds polyatomic ions which are the smallest particles. Polyatomic ionic compound composed of cations and anions, namely:1) Compound Salts of polyatomicThe salt compound is a compound salt polyatomic cation or anion is polyatomic ion.2) Basa CompoundAccording to Arrhenius, bases are substances that can release OH-ions in water. Base solution slightly bitter taste and is kausatik (slippery as soap). Basic compounds are ionic compounds consisting of metal cations and anions OH-(except NH4OH). Basic compounds can be formulated as follows.
L: metalOH-: hydroxide (the nature of base)x: valence basa (similar to numbers oxide L)Naming the basic compounds are as follows: alkaline compounds formed by a metal ion yng have sole charge. For example, alkali, alkaline earth metals, and aluminum. Naming compounds are formulated as follows:
base formed by the metal ions have multiple charges, naming compounds are formulated as follows:
• Covalent compounds polyatomicPolyatomic covalent compound is a compound that polyatomic molecule is the smallest particle. The compound belongs to the polyatomic covalent compound is a compound oxyacid.Naming oxyacid compounds are as follows.1) the only non-metallic elements form a compound, the compound ends-at.2) non-metallic element that forms two types of amino acid, which has a lot of oxygen ends-at.3) oxy-halogen acid is an acid that has an acidic oxide and a halogen oxides. In simple terms, means oxyacid halogen atom acid center is the halogen elements. Naming acids halogen oxides depends on the oxidation state or the amount of oxygen.2. Nomenclature of Organic Compoundsa. Simple Hydrocarbon CompoundsHydrocarbon compounds are classified as alkanes, alkenes, and alkynes. The division of these compounds is based on the existence of double bonds in the hydrocarbon compounds.IUPAC
nomenclature for alkenes and alkynes compounds based on the
nomenclature of alkanes with the number of C atoms corresponding to the
change akhirannya match the name of each compound.Comparison of Names Simple Organic CompoundsNumber of atoms C Name Alkanes Alkenes Name Name alkyne1 Methane -2 Ethane Ethene ethyne3 Propane propene Propuna4 Butane Butene ButunaPentane 5 Pentena Pentuna6 Hexane hexene Heksuna7 heptane Heptena Heptuna8 octane octene Oktuna9 Nonana Nonena Nonuna10 decane Dekena Dekunab. Simple Alcohol CompoundsTata nana alcohol compound similar to the nomenclature of simple hydrocarbons. Naming, modest alcohol compounds are as follows.CH3OH: MethanolC2H5OH: EthanolC3H7OH: Propanolc. Organic Acid CompoundsOrganic acids or carboxylic acids by IUPAC called alkanoic acids. General formula is R-COOH. Naming sorted as follows.R (alkyl) is an alkane missing one atom H.B. The law - the law of Basic Chemicals
• LAW OF CONSERVATION OF MASS (Lavoisier LAW)"The mass of substances before and after the reaction is fixed".Example:hydrogen + oxygen = hydrogen oxide(4g) (32g) (36g)
• FIXED COMPARATIVE LAW (LAW Proust)"Comparison of the mass of the elements in each compound is fixed"Example:a. In the compound NH3: N mass: mass of HAr = 1. N: 3 Ar. H= 1 (14): 3 (1) = 14: 3b. On the compound SO3: S mass: mass 0Ar = 1. S: 3 Ar. O= 1 (32): 3 (16) = 32: 48 = 2: 3Advantages of the law Proust:if
known mass of a compound or a mass of one of the elements that make up
the compound is the mass of other elements could be determined.Example:How many levels of C in 50 grams of CaCO3? (Ar: C = 12; 0 = 16; Ca = 40)Mass C = (Ar C / Mr CaCO3) x mass of CaCO3= 12/100 x 50 grams = 6 gramsmass CLevels of C = mass C / mass x 100% CaCO3= 6/50 x 100% = 12%
Deviations from the law Proust
Please note that while this law is very useful in the fundamentals of modern chemistry, comparative law still does not always apply to all compounds. Compounds that do not comply with this law are called non-stoikiometris compounds. Mass ratio of the elements in the non-stoikiometris compounds vary in different samples. For example, iron oxide wüstite, has a ratio of between 0.83 to 0.95 iron atoms for every oxygen atom. Proust did not know this because of the equipment he uses is not accurate enough to distinguish this figure.
In addition, the law also does not apply to Proust compounds containing different isotopic compositions. Isotopic composition may vary according to the source of the elements that make up the compound. This difference can be used to chemically calendar, because the processes astronomical, atmospheric, and processes in the oceans, Earth's crust and the inside is sometimes have a tendency toward heavy or light isotopes. Caused very little difference, but it can usually be measured with modern equipment. In addition, the law also does not apply Proust in polymers, both natural and artificial polymers polymers.
• LEGAL COMPOUND = COMPARATIVE LAW DALTON"When
the two elements can form two or more compounds to the mass of one
element as much the second element of the mass ratio in value as
integers and simple".Example:If the element nitrogen fertilized den oxygen can be formed,NO where mass N: 0 = 14: 16 = 7: 8NO2 which the mass N: 0 = 14: 32 = 7: 16For the same amount of nitrogen mass ratio of the mass of oxygen in the compound NO: NO2 = 8: 16 = 1: 2
• GAS LAWS To apply the ideal gas equation: PV = nRTwhere:P = gas pressure (atmospheric)V = gas volume (liters)n = moles of gasR = universal gas constant = 0082 lt.atm / mol KelvinT = absolute temperature (Kelvin)The changes of P, V and T from state 1 to state 2 with certain conditions reflected by the following laws:
BOYLE LAW This law is derived from the ideal gas equation of state withn1 = n2 and T1 = T2; thus obtained: P1 V1 = P2 V2LEGAL Gay-Lussac"The
volume of gases that react den gas volume of reaction when measured at
the same temperature and pressure, will be compared as integers modest
den".So for: P1 = P2 and T1 = T2 holds: V1 / V2 = n1 / n2BOYLE LAW-Gay LussacThis law is an extension of the previous law is spoken with the state price den n = n2 to obtain the equation:P1. V1 / T1 = P2. V2 / T2Avogadro's law"At
the same temperature and pressure, gases equal volume containing the
same number of moles. From this statement it is determined that the
state of STP (0o C 1 atm) 1 mole of any gas volume of 22.4 liters of
volume is referred to as the molar volume of gas.Example:What volume of 8.5 g of ammonia (NH3) at a temperature of 27o C and a pressure of 1 atm?(Ar: H = 1, N = 14)Answer:85 g of ammonia = 17 mol = 0.5 molThe volume of ammonia (STP) = 0.5 x 4.22 = 2.11 litersAccording to Boyle-Gay Lussac equation:P1. V1 / T1 = P2. V2 / T21 x 112.1 / 273 = 1 x V2 / (273 + 27). V2 = 12:31 litersC. Reaction Equations
Equation has the properties:1) Type of the elements before and after the reaction is always the same2) The number of each atom before and after the reaction is always the same3)
Comparison of the reaction coefficient expressed mole ratio (ratio of
specific gaseous volume ratio coefficient is also said as long as the
same temperature and pressure)Step-by-Step Writing Reaction Equations1) The names of the reactants and reaction products listed. The writing is calledequality predicates.2) Write the equation using the symbols, iechemical formulas of substances, and the form of the reaction. The writing is called equality framework.3) Balance the equation to obtain the equation kerangksequivalent reaction is called chemical equation.Equivalency equationEquivalency equation Raksi lawful immune reaction Lavoisier and Dalton's atomic theory. According to the law of Lavoisier, the chemical reaction does not change the mass. That
is, the number and type of atoms on the left (reactants) is equal to
the number and type of atoms on the right (the reaction). As
per Dalton's atomic theory, chemical reactions no atoms lost or
created, all that happened was the rearrangement of the atoms forming
reactants new arrangement, the reaction products. To
be kind and number of atoms on the left the same as in the right-hand
side, the equation equivalent (balanced) by arranging the numbers in
front of the reactants and reaction products. Figures given in front of the reactants and reaction products are called coefficients. Number one as coefficient is omitted. Therefore, the equation can be written as follows.Stages equalization equation can be done by:1)
Write the equation of the framework, which is not equivalent to the
equation, the reactants on the left and the reaction on the right.2) Set the coefficient of the substance / compound is a more elaborate one.3) Balance the reaction by adjusting the coefficients of the reactants and reaction products to another.
D. Mol Concepts
mole is the amount of the chemical unit numbers of the atoms or molecules of Avogadro's number and mass = Mr compound.If Avogadro's number = L then:L = 6.023 x 10231 mole of atoms = L atoms, mass = Ar atom.1 mole of molecules = L = Mr fruits molecular mass of the molecule.The mass of one mole of a substance is called the molar mass of the substanceExample:How many molecules are present in 20 grams of NaOH?Answer:Mr NaOH = 23 + 16 + 1 = 40mol NaOH = mass / Mr = 20/40 = 0.5 molThe number of molecules of NaOH = 0.5 L = 0.5 x 6023 x 1023 = 3.01 x 1023 molecules.Mol relationship with the number of particlesIt is known that substances 1mol X = l fruit particles of matter X, then2 moles of substance X = 2 x L particles of substance X5 moles of substance X = 5 x L particles of substance Xn moles of substance X = n x L particles of substance XThe number of particles = n x L
Future Atom and The Formula1) Atomic MassAtomic mass is defined as the mass of an atom in atomic units of mass units (amu) or atomic mass units (sma). One amu is defined as 1/12 times the mass of one atom of C-12. Carbon-12 is one isotope of carbon has 6 protons and 6 neutrons. This element is used as a standard of comparison for these elements have properties that are very stable with long half-lives. By setting an atomic mass of 12 C-12 sma, we can determine the mass of atoms of other elements. For example, it is known that the hydrogen atom has a mass of only 8.4% of the mass of one atom of C-12. Thus, the mass of a hydrogen atom is 8.4% or 1.008 x 12 sma sma. By similar calculations, one can obtain the mass of the oxygen atom is 16.00 sma and an atomic mass of iron is 55.85 sma. This means that a single iron atom has a mass about 56 times the mass of a hydrogen atom.2) Relative Atomic Mass (Ar)Atomic mass of the element of truth can not be measured by weighing the mass of atoms, because atoms are so small. Atomic
mass of the element is determined by comparing the average atomic mass
of the element to 1/12 the average mass of one atom of carbon-12 so
obtained is the atomic mass relative atomic mass (Ar).3) Relative Molecular MassElements and compounds in the form of molecular particle, its mass is expressed in relative molecular mass (Mr). Basically
the relative molecular mass (Mr) is the ratio of the average mass of a
single molecule of an element or compound with 1/12 the average mass of
one atom of carbon-12.
So many types of molecules, so no table relative molecular mass. However, the relative molecular mass can be calculated by adding the relative atomic mass of the atoms that form the molecule.Mr = ΣArTo compound the particle is not shaped molecules, but pair ions, such as NaCl then Mr. compound called relative formula mass. Relative
formula mass is calculated in the same way as the calculation of the
relative molecular mass, ie by adding the relative atomic mass of the
elements in the formula of the compound.4) Molar MassIt
is known that a mole is the amount of substance containing particles
(atoms, molecules, ions) as there are atoms in 12 grams of carbon with
mass number 12 (carbon-12, C-12). So it looks that the mass of one mole of C-12 is 12 grams. The mass of one mole of a substance is called the molar mass. Molar mass equal to the relative molecular mass (Mr) or relative atomic mass (Ar) of a substance expressed in grams.Molar Mass = Mr or Ar a substance (g)
5) Molar VolumeAvogadro
get the results of experiments that at a temperature of 0 ° C (273 K)
and a pressure of 1 atmosphere (76cmHg) got exactly 1 liter of oxygen to
the mass of 1.3286 grams.
Kamis, 11 Oktober 2012
Selasa, 09 Oktober 2012
ATOM, ION AND MOLECULES (CH 2)
Understanding
Atom
Atom is the smallest part of an element that still has the properties of that element. Each atom of an element have different properties to the atomic nature of the other elements.
Atom is the smallest part of an element that still has the properties of that element. Each atom of an element have different properties to the atomic nature of the other elements.
Development of Atomic Theory
- In 400 BC Democritus and Leucippus states that all matter is composed by particles are very small and can not be divided again. And then they named the atom with greek (atomos: a = no, Tomos = cut or split). Whereas Aristotle states that matter is continuous, meaning that the material can be split or shared continuously without limit.
- In 1803 John Dalton (1766-1844) Atomic Model Dalton à states:
· The material is composed of small particles tidakdapat divided again,
· Atoms of the same (an element) has the same properties
· Atoms can join together chemically to form moleku
Weaknesses: does not explain the difference between atomic elements with other atoms
- In 1898 JJ Thomson (1856-1940) stated à Thomson Atomic Model:
· Atomic incandescent spherical positively charged and contains a number of electrons in the negatively charged atoms
· The number of positive and negative charges the same, so the charge is neutral atoms
- In 1911 Ernest Rutherford (1887-1931) Model àmenyatakan Rutherford:
· Atomic nucleus contains positively charged atom in the center and surrounded by negatively charged electrons
Weakness: not able to explain why the electrons do not fall into the nucleus due to the gravity of the core electrons
- Niels Bohr Model à states
· Electrons can spin only through a particular trajectory
· If the electron perpindah kelintasan deeper, it will be emitted energy whereas when you go out it will be absorbed energy
Weaknesses: can not explain the spectrum of colors from many electron atoms.
- Erwin Schrodinger and Warner Heisenbreg (1925-1926) stated à-Heisenbreg Schrodinger Atomic Model: electrons can be determined only possible where it is, which is located in a space called the electron cloud.
- In 400 BC Democritus and Leucippus states that all matter is composed by particles are very small and can not be divided again. And then they named the atom with greek (atomos: a = no, Tomos = cut or split). Whereas Aristotle states that matter is continuous, meaning that the material can be split or shared continuously without limit.
- In 1803 John Dalton (1766-1844) Atomic Model Dalton à states:
· The material is composed of small particles tidakdapat divided again,
· Atoms of the same (an element) has the same properties
· Atoms can join together chemically to form moleku
Weaknesses: does not explain the difference between atomic elements with other atoms
- In 1898 JJ Thomson (1856-1940) stated à Thomson Atomic Model:
· Atomic incandescent spherical positively charged and contains a number of electrons in the negatively charged atoms
· The number of positive and negative charges the same, so the charge is neutral atoms
- In 1911 Ernest Rutherford (1887-1931) Model àmenyatakan Rutherford:
· Atomic nucleus contains positively charged atom in the center and surrounded by negatively charged electrons
Weakness: not able to explain why the electrons do not fall into the nucleus due to the gravity of the core electrons
- Niels Bohr Model à states
· Electrons can spin only through a particular trajectory
· If the electron perpindah kelintasan deeper, it will be emitted energy whereas when you go out it will be absorbed energy
Weaknesses: can not explain the spectrum of colors from many electron atoms.
- Erwin Schrodinger and Warner Heisenbreg (1925-1926) stated à-Heisenbreg Schrodinger Atomic Model: electrons can be determined only possible where it is, which is located in a space called the electron cloud.
Atomic Structure
Ø atomic model that can be used to study the atomic structure is Rutherford and Bohr model of the atom.
Ø Bohr's atomic model is similar to the position of the sun to the planets in the solar system. The mass of the nucleus is much larger than the electron mass. Therefore, the electrons surrounding the nucleus.
- Atoms consist of a nucleus and electrons. The nucleus is composed of protons and neutrons.
- Protons are positively charged (+), uncharged neutrons (neutral), while the electrons are negatively charged (-). Same number of electrons and protons, so the atom becomes neutral charge.
- The number of protons and electrons are expressed as atomic number, number of protons and neutrons is expressed as the mass of the atom. Arrangement of atoms can be written using the following notations:
Rounded Rectangle: (_ ^ A) X_z ^ Description:
X = symbol element
A = atomic mass = number of protons + number of neutrons
Z = atomic number = number of protons = number of electrons
A-Z = Number of neutrons
Ø atomic model that can be used to study the atomic structure is Rutherford and Bohr model of the atom.
Ø Bohr's atomic model is similar to the position of the sun to the planets in the solar system. The mass of the nucleus is much larger than the electron mass. Therefore, the electrons surrounding the nucleus.
- Atoms consist of a nucleus and electrons. The nucleus is composed of protons and neutrons.
- Protons are positively charged (+), uncharged neutrons (neutral), while the electrons are negatively charged (-). Same number of electrons and protons, so the atom becomes neutral charge.
- The number of protons and electrons are expressed as atomic number, number of protons and neutrons is expressed as the mass of the atom. Arrangement of atoms can be written using the following notations:
Rounded Rectangle: (_ ^ A) X_z ^ Description:
X = symbol element
A = atomic mass = number of protons + number of neutrons
Z = atomic number = number of protons = number of electrons
A-Z = Number of neutrons
Electron Configuration
- Electrons surround the nucleus of an atom on the trajectories (shells) with a certain energy level. The arrangement of electrons in an atom is called the electron configuration shell.
- The number of electrons that can be accommodated masimum each skin is 2N2 where n is the number of skin. For the first 20 elements of the outer shell is not more than 8 electrons, for example, potassium has 19 electrons and its configuration is not 2 8 8 1 2 8 9.
Ø Ion
ü Ions are electrically charged particles that are formed when an atom loses an electron or or more to form a stable outer shell. Ion that lost an electron positively charged (cations) and the capture of an electron is negatively charged (anionic).
ü event release or influx of ions is called ionization. Ion was first discovered by the German physicist, Julius Elster and Hans Friedrich Geitel in 1899.
ü Proton is located in the nucleus of an atom that prtoton hard to get out of the atom. To remove the proton required enormous energy (nuclear reaction). Electrons are outside the nucleus (around the nucleus of an atom in a particular orbit) so that the electrons can leave a an atom. Furthermore, the electron is accepted by the other atom. In other words, an atom can release or accept electrons.
- Electrons surround the nucleus of an atom on the trajectories (shells) with a certain energy level. The arrangement of electrons in an atom is called the electron configuration shell.
- The number of electrons that can be accommodated masimum each skin is 2N2 where n is the number of skin. For the first 20 elements of the outer shell is not more than 8 electrons, for example, potassium has 19 electrons and its configuration is not 2 8 8 1 2 8 9.
Ø Ion
ü Ions are electrically charged particles that are formed when an atom loses an electron or or more to form a stable outer shell. Ion that lost an electron positively charged (cations) and the capture of an electron is negatively charged (anionic).
ü event release or influx of ions is called ionization. Ion was first discovered by the German physicist, Julius Elster and Hans Friedrich Geitel in 1899.
ü Proton is located in the nucleus of an atom that prtoton hard to get out of the atom. To remove the proton required enormous energy (nuclear reaction). Electrons are outside the nucleus (around the nucleus of an atom in a particular orbit) so that the electrons can leave a an atom. Furthermore, the electron is accepted by the other atom. In other words, an atom can release or accept electrons.
The valence electrons:
- Establishment of positive ions à atom loses electrons
- The formation of negative ions capture electrons à atom
- Ionikàsenyawa compound formed from positive ions and negative ions bond together to form a neutral compound. Ionic compounds have a high melting point. That's because the compound there is a very strong bond between the ions forming
Ø Molecular
ü The molecule is the smallest part of a compound and still have the properties of these compounds. In other words, the molecule is a combination of two or more atoms chemically.
ü Based on the types of atoms that make up molecules, molecules are divided into two, namely:
- Molecular Elements à bunch of atoms of the same element chemically combine to form a molecule. In other words, the molecule consists of only one type of constituent atoms.
The molecule can be divided into two elements, namely:
· Molecular diatomikàmolekul element composed of two atoms of the same. Example: H2 (hydrogen), O2 (oxygen gas)
· Molecular poliatomikà molecular elements composed of more than two of the same atom. Example: P4, S8
Examples of elements of hydrogen formation
ü Each hydrogen atom has satuelektron
ü electrons are trying to form a stable electron configuration, ie two (the maximum number of electrons on the skin to-1)
ü The two electrons have enough power to attract each other
ü The atoms used by two atoms (sharing)
ü Each nucleus has two electrons in the atomic shell.
Covalent bond
ü bonds are bonds that form due to the use of electrons together
ü Iakatan covalent ionic bond is less powerful than
ü If there is 1 atom pairs are used together, it is called a single covalent bond
ü If there are 2 pairs of atoms that are used together, it is called a double covalent bond
ü The electrons are not shared are called nonbonding electrons (bonding = bond)
ü covalent Senayawa not conduct electricity because it does not form ions are electrically charged.
- Molecular compounds à compounds composed of more than one type of constituent atoms.
Example: H2O (water), CO2 (carbon dioxide)
Examples formation of water molecules
ü The water molecule consists of two atoms of H and 1 atom O
ü Atomic H has 1 electron in its outer shell
ü Atom O has 6 electrons in its outer shell
ü Each H atom to one electron eletron by pulling 2 of 2 atoms O
ü Atom O requires two atoms. The trick is to draw two electrons of two atoms H
ü There are two covalent bonds.
Ø Atoms, Ions, Molecules in Daily Chemical Products
ü Breathing a breath of air molecules udaramengandung elements such as oxygen (O2), nitrogen (N2), and the molecules of compounds such as carbon dioxide (CO2) emissions.
ü The sweetness of sugar molecules composed of sugar or sucrose (C12H22O11).
ü taste sour pickles, a few drops of vinegar derived from molecules containing vinegar (CH3COOH).
ü kitchen salt derived from a chemical compound that is NaCl, which if dilarut in water into ions Na + and Cl-
ü Gasoline or diesel fuel composed of hydrocarbon molecules
ü Glass, glasses, plates consist of molecules of silica oxide (SiO2)
ü plastic polymers include polyethylene, polypropylene, polyurethane, and PVC
ü polymer is polyisoprene rubber and polystyrene.
- Establishment of positive ions à atom loses electrons
- The formation of negative ions capture electrons à atom
- Ionikàsenyawa compound formed from positive ions and negative ions bond together to form a neutral compound. Ionic compounds have a high melting point. That's because the compound there is a very strong bond between the ions forming
Ø Molecular
ü The molecule is the smallest part of a compound and still have the properties of these compounds. In other words, the molecule is a combination of two or more atoms chemically.
ü Based on the types of atoms that make up molecules, molecules are divided into two, namely:
- Molecular Elements à bunch of atoms of the same element chemically combine to form a molecule. In other words, the molecule consists of only one type of constituent atoms.
The molecule can be divided into two elements, namely:
· Molecular diatomikàmolekul element composed of two atoms of the same. Example: H2 (hydrogen), O2 (oxygen gas)
· Molecular poliatomikà molecular elements composed of more than two of the same atom. Example: P4, S8
Examples of elements of hydrogen formation
ü Each hydrogen atom has satuelektron
ü electrons are trying to form a stable electron configuration, ie two (the maximum number of electrons on the skin to-1)
ü The two electrons have enough power to attract each other
ü The atoms used by two atoms (sharing)
ü Each nucleus has two electrons in the atomic shell.
Covalent bond
ü bonds are bonds that form due to the use of electrons together
ü Iakatan covalent ionic bond is less powerful than
ü If there is 1 atom pairs are used together, it is called a single covalent bond
ü If there are 2 pairs of atoms that are used together, it is called a double covalent bond
ü The electrons are not shared are called nonbonding electrons (bonding = bond)
ü covalent Senayawa not conduct electricity because it does not form ions are electrically charged.
- Molecular compounds à compounds composed of more than one type of constituent atoms.
Example: H2O (water), CO2 (carbon dioxide)
Examples formation of water molecules
ü The water molecule consists of two atoms of H and 1 atom O
ü Atomic H has 1 electron in its outer shell
ü Atom O has 6 electrons in its outer shell
ü Each H atom to one electron eletron by pulling 2 of 2 atoms O
ü Atom O requires two atoms. The trick is to draw two electrons of two atoms H
ü There are two covalent bonds.
Ø Atoms, Ions, Molecules in Daily Chemical Products
ü Breathing a breath of air molecules udaramengandung elements such as oxygen (O2), nitrogen (N2), and the molecules of compounds such as carbon dioxide (CO2) emissions.
ü The sweetness of sugar molecules composed of sugar or sucrose (C12H22O11).
ü taste sour pickles, a few drops of vinegar derived from molecules containing vinegar (CH3COOH).
ü kitchen salt derived from a chemical compound that is NaCl, which if dilarut in water into ions Na + and Cl-
ü Gasoline or diesel fuel composed of hydrocarbon molecules
ü Glass, glasses, plates consist of molecules of silica oxide (SiO2)
ü plastic polymers include polyethylene, polypropylene, polyurethane, and PVC
ü polymer is polyisoprene rubber and polystyrene.
Sabtu, 06 Oktober 2012
CHEMICAL REACTION
CHEMICAL REACTION
CHEMICAL REACTION EQUALIZATION
The basis for equalizing the chemical reaction is the law of mass eternity filed by Lavoiser, and stated "In a reaction, the mass of substances before reacting equal to the mass of the substance after reacting". This suggests to us that there is no mass loss during the ongoing reaction.In a chemical equation, there are two areas, the area where the substance before reacting to the left of the arrow and the area where the substance has reacted in the right arrows.In both these areas, we will get the information that the substances before and after the reaction is the same, the same can be shown to equal the number of atoms, or the number of masses. The example below can explain what information we can from the equationC + O2 → CO2This equation is true if the number of carbon atoms on the left arrow (before reaction) equal to the number of atoms right arrows (after reaction). Similarly, the oxygen atom before and after the reaction is the same.It appears that the number of C atoms on the left and right are the same, as many as 1 piece. Similarly, for the same number of O atoms is 2 pieces. Thus the equation is correct.Other information is the amount of Carbon and Oxygen mass before and after the reaction is the same, for example, there are 12 grams of carbon and 32 grams of oxygen before reacting, based on the equality of the number of atoms of the same, then automatically the amount of a substance that occurs has the same mass composition. CO2 compounds, containing 12 grams 32 grams C and O.Generally rudimentary written equation, where the number of atoms before and after the reaction has not been the same as:N2 + H2 → NH3The number of atoms N as left arrows 1 piece, right arrows 1 piece, so that the arrows on the right multiplied by 2. As a result of multiplying the number of H atoms next to it into 6 pieces, while on the left there are 2 pieces. To balance the H atom, the H atom left multiplied by 3. Figures multiplier used to menyetarakanan reaction, then entered into the equation.
GROUPING CHEMICAL REACTION
The diversity of chemical reactions and approaches taken in the study resulted in many ways to classify these reactions, which often overlap. Below are examples of classification of chemical reactions that are normally used.Four basic reaction
Synthesis
In direct combination or synthesis reaction, two or more simple compounds combine to form a new, more complex compound. Two or more reactants react to produce a product that is also one way to find out if it is the synthesis reaction. An example of this is the reaction of hydrogen gas with oxygen gas combine the result is water.Another example is nitrogen gas combine with hydrogen gas to form ammonia, by the equation:N2 + 3 H2 → 2 NH3
Dekomposisisi
Decomposition reaction is the opposite of analysis or synthesis reactions. A more complex compounds are broken down into simpler compounds. Examples are water molecules are split into hydrogen gas and oxygen gas, with the equation:2 H2O → 2 H2 + O2
Single replacement
In a single replacement or substitution reaction, a single element of a single element replaces another in a compound. Examples are sodium metal reacts with hydrochloric acid will produce sodium chloride or table salt, the reaction persamaaan:2 Na (s) + 2 HCl (aq) → 2 NaCl (aq) + H2 (g)
Replacement double
In a double replacement reaction, two compounds or ions change each bond to form new compounds are different. This occurs when the cations and anions of two different compounds each move, and form two new compounds. The general formula of this reaction is:AB + CD → AD + CBAn example of a double replacement reaction is lead (II) nitrate reacts with potassium iodide to form lead (II) iodide and potassium nitrate, with the equation:Pb (NO3) 2 + 2 KI → PbI2 + 2 KNO3Another example is sodium chloride (table salt) reacts with silver nitrate to form sodium nitrate and silver chloride, the reaction equation:NaCl (aq) + AgNO3 (aq) → NaNO3 (aq) + AgCl (s)
CHARACTERISTICS OF CHEMICAL REACTION
1. Colour Change Happen In a chemical reaction, reactants are converted into products. Changes may occur due to the termination of the bonds of the reactants and the formation antaratom ties bru that make up the product. Energy required to break the tie. To form a new bond, released some energy. Thus, the chemical reaction energy changes.Chemical reactions that produce energy in the form of heat is called exothermic reactions. Reactions that absorb heat energy called endothermic reactions.Example: Fire can warm up a cold and when hot breath in the body due to exercise so that the body becomes cold expelled.
2. Temperature changes occurIn a chemical reaction, reactants are converted into products. Changes may occur due to the termination of ties antaratom reagents and formation of new bonds that make up the product. Energy required to break the tie.Chemical reactions that produce energy in the form of heat is called exothermic reaction, while the reaction absorbs heat energy called endothermic reactions.A chemical reaction occurs in a space that we call dbngan system, places outside the system is called the surroundings.In exothermic reactions, heat transfer occurs from sisitem to the environment.In endothermic reactions occur transfer heat energy from the environment to the system.
3. Sediment formation occursWhen two solutions react in a test tube, sometimes forming an insoluble sneyawa, solid, and separated from the solution. The solid is called the precipitate (precipitate)
4. Gas Formation occursSimply put, the chemical reaction created a gas which indicated the presence of bubbles in solution reacted. The gas can be determined from the typical smell, like sour sulfide (H2S) and ammonia (NH3), which stinks.
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