Minggu, 27 Agustus 2017
Minggu, 13 Agustus 2017
TINJAUAN ULANG TENTANG ATOM DAN MOLEKUL DALAM KIMIA ORGANIK
Dalam segolongan, jari-jari atom akan
semakin besar dari atas ke bawah. Hal ini terjadi karena dari atas ke bawah
jumlah kulit bertambah sehingga jari-jari atom juga bertambah.
Kelektronegatifan adalah kemampuan suatu
atom untuk menarik elektron dari atom lain. Faktor yang mempengaruhi keelektronegatifan
adalah gaya tarik dari inti terhadap elektron dan jari-jari atom.4. Energi Disosiasi
Jumat, 26 Mei 2017
Chemistry Video Coloid
A. UNDERSTANDING COLOIDColloid is a form of a homogeneous phase-shift mixture (of a kind) to be heterogeneous. The mixture is the state between the solution and the suspension. In macroscopic colloids appear homogeneous, but in fact colloids are classified as heterogeneous mixtures, because the differences in both colloidal phase particles can still be observed and differentiated macroscopically.
Like a sugar or salt solution, the particles may contain more than one molecule but are not large enough to be seen with a regular microscope. The particles located within a distance of colloidal size have a very large surface area compared to the surface area of larger particles of the same volume.
The dispersion system is a system in which a substance is fine or dispersed in another substance. Colloid is a dispersion system, because it consists of two phases, namely the dispersed phase, and the dispersing phase.COLLOIDB. CHOLOID PROPERTIES1. Optical propertiesOptical properties of colloids are properties that can scatter light. This event is called the Tyndall Effect. In everyday life, this effect can be observed as in a cinema where smoke billows will make the projector light brighter, foggy areas (highlight the lights more clearly), sunlight entering through the gap will make the dust particles appear more clearly.
When light is passed through a medium containing particles less than 10-9 m, the light beam can not be detected from the medium called optically clear. When the colloidal particles are present, however, some of the light will be scattered, and some will be continued in low intensity.
The Tyndall effect can be used to observe colloidal particles using a microscope. Because the intensity of light scattering depends on particle size, the Tyndall effect can also be used to estimate the weight of colloid molecules. Colloidal particles of small size, tends to scatter light with short wavelengths. Conversely large colloidal particles tends to scatter light with longer wavelengths
2. Kinetic natureThis property consists of two movements, namely thermal movement and movement due to the force of gravity. Colloid particles move continuously with the movement of a broken or zig-zag known as Brownian motion.
Brown motion occurs due to unbalanced collision of medium molecules against colloidal particles.
Colloidal particles have a tendency to precipitate due to the effects of earth's gravity. It depends on the particle mass density of the medium. If the mass density of the particle is larger than the dispersing medium, then the particle will precipitate. Conversely, if the smaller mass meeting will float.
The solute particles will diffuse from the high concentration solution to the lower concentration areas. Diffusion is closely related to Brownian motion, so it can be considered colloid molecules or particles diffuse due to Brownian motion. Colloidal grains diffuse very slowly because of their relatively large particle size.
3. Physical PropertiesThe properties of colloidal physics vary depending on the type of colloid. In hydrophobic colloids the properties are density, the surface tension and viscosity are almost identical with the dispersing medium. In hydrophilic colloid due to hydration, the physical properties are very different from the medium. Its viscosity (thickness) is larger and its surface tension is relatively smaller.
4. Electrical PropertiesThe colloidal particles have their surface charge caused by ionizing or absorbing the charge. When the charged colloidal particles are placed in an electric field, the particle will move toward one electrode depending on its charge, this process is known as electrophoresis.
5. Adsorption PropertiesAdsorption is the process of attaching a substance to a solid or liquid surface. Colloidal particles are easy to adsorb color. The size of small colloidal particles so that the surface is large and causes great adsorption ability.
6. Coagulation propertiesCoagulation is a clumping of colloidal particles, so the stability of the colloidal system is lost. The cause of coagulation in the colloidal system due to the influence of heating, cooling, electrolyte mixing, and electrophoresis that lasts long. Examples of coagulation such as boiling raw eggs in water, cooling hot agar, and purifying river water.
7. Protective PropertiesIt is a colloidal system added to other colloids, resulting in a stable colloid. Like the addition of gelatin to ice cream, to produce soft ice cream.
Supporting Articles: Electrolyte and Non-Electrolyte Solutions
C. TYPES OF KOLOIDBased on the dispersed phase, the colloidal system is divided into 3, ie soles, emulsions, and foams
Sol, solid dispersed phase.
D. CHOLORY CHARACTERISTICS
Molecular dispersion
The nature of the colloidal mixture is heterogeneous.
The particle dimension is less than 1 nm, so it needs a special microscope to observe colloids.
Although colloids are heterogeneous, colloids can not be filtered. Like seawater that also contains salt therein, but after screening also did not get results.
The stable colloidal system is caused by the pulling force (London-van der waals), which causes colloidal particles to converge to aggregate and precipitate. Also due to repulsive force caused by overlapping of electrically charged double layer layers.
Examples of colloids such as sugar solution, salt solution, alcohol, vinegar, spiritus, sea water, gasoline, and clean air.
E. COLOID UTILIZATIONColloids are widely used in industry because they do not dissolve the mixture homogeneously, it is stable, and is not easily damaged.Use of colloids in industry:
1. Cosmetic industryMany use emulsions and froths, such as foundation, shampoo, facial cleanser, deodorant, and body moisturizer.
2. Textile IndustryTextile dye in the form of soles makes the colors absorb well.
3. Pharmaceutical IndustryMedicines are mostly made in the form of soles.
4. Industrial soaps and detergentsSoaps and detergents are emulsifying dirt and water on clothing that keeps clothes clean
5. Food and beverage industryFood and beverages such as soy sauce, sauce, milk, mayonnaise, and butter are made in various forms of colloids.
Colloids also have beneficial properties. As :1. Tyndall effectIn cinemas with clearer lights, lampshades are made of colloids so they can scatter light.
2. Properties of ElectrophoresisWhich is used for DNA identification as well as victims of crime
3. The properties of adsorption3a. Bleaching cane sugarThe red color of sugar cane is adsorbed by diatomaceous soil, by dissolving sugar in water, then flowing through the soil of diatoms.
3b. Purifying waterConducted by adding water with Tawas or aluminum sulfate absorbing water pollutants, activated carbon for very high pollution, add sand as filter, chlorine as desingektan, lime toad increase pH value due to alum use.
4. Properties of Coagulation4a. Rubber clumping4b. Purifying waterThe mud in the water is coagulated by using alum4c. Disposal of factory smokeBefore being thrown into the chimney, smoke flows into a high-voltage metal (20-75 kV) so that the surrounding air molecules are ionized. These ions are adsorbed by smoke so smoke has a charge. Then the smoke is pulled by another electrode so that the gases removed are free of smoke.
5. Colloid Protector5a. Emulsifiers such as soap5b. Milk is protected by casein which prevents fat clots5c. Butter is protected by lecithin that prevents fat clots5d. Ice cream is protected by gelatin which prevents the formation of sugar crystals or ice cubes.5e. Ink and paint are protected by silicone oils that make ink and paint last longer
Senin, 22 Mei 2017
Chemical Article
A QUANTUM DYNAMIC APPROACH TO THE CONDENSATION PROCESSES OF ZINC ATOMS BY THE INNER-CORE EXCITATION DUE TO ION RECOMBINATION
Mitsugi Hamasaki1*, Masumi Obara1 , Kozo Obara1 , Hirotaka Manaka1 1 Graduate School of Science and Engineering Kagoshima University, Korimoto 1-21-40, Kagoshima, 8900065, Japan
ABSTRACT
Isolated atoms in group II-B such as zinc (Zn), cadmium (Cd), and mercury (Hg) are chemically stable. These atoms are important in the formation of excimer. Zinc in particular has been investigated by many researchers, as Zn2 excimer holds promise because of its long lifetime and its potential as an energy-storage system. However, excimer’s benefits are based on excitation of the outermost electron. Our study confirmed the quantum dynamical condensation processes in which inner-core excitation arises due to ion-recombination between the vapor phase and the solid phase. The X-ray diffraction of the condensed structure of zinc film had included strong diffuse scattering depending on the incident energies. In this research, we produced the excited state of zinc excimer characterized by an extremely long lifetime. Intriguingly, a feature of the zinc film is that it transforms from metallic to insulative. It is thought that such a structure with this characteristic has been affected by electron spin and atomic distortion by inner-core excitation. The structure obtained in our experiment is expected to prove promising in engineering applications, such as electronics, spintronics, and batteries.
1. INTRODUCTION
In the vapor phase growth processes, condensation is a most important process in which the translational kinetic energy of incident atoms in the gas phase is dissipated at the crystal surface (Ehrlich & Hudda, 1966). So far, incident energy has been treated as independent from the surface atom system because the surface of the atom system is neutral (Bendavid et al., 2000). In this paper, we propose a method to analyze the quantum dynamic processes in the condensation process from vapor phase to solid phase. We respect the parity of the incident particles. Since the analysis of the particles with the same parity is impossible, we adopted particle systems having different parities. The simplest way to adopt the particles having different parities is obtained by the ionizing in opposite polarities. Normally the lifetime of negative ions is much shorter than that of positive ones (Herzberg, 1944); a unique approach is needed to elongate the lifetime of the negative ions. For this research, a negatively charged crystal surface with electron irradiation was used.
The condensation of a positive ion and a negative ion is called the ion-recombination process. The Coulomb force between two ions with opposite polarities produces a strong cohesive force. The translational kinetic energy of the incident ions dissipates at the first collision of these two ions. The most effective process for energy dissipation in this process is the energy transfer from translational energy to e internal energy in the ion’s electron system. In order to detect these quantum dynamic processes, we used X-ray diffraction techniques for detecting the spatial correlation between the two atoms. X-ray diffraction intensities clearly depended on the energies of electron irradiation. We found strong diffuse scattering of X-rays on the thin films of zinc deposited by electron irradiation. The strong diffuse scattering indicates the existence of a lattice defect in the thin film observed at the discrete energies of electron irradiation. Further strong Bragg reflection intensities were observed at the discrete energies. These energies correspond to the binding energies of a zinc atom: 3d(10eV), 3p(90 eV), and 3s(140 eV). These experimental data show the evidence of inner-electron excitation of zinc ions. These electron energies have been dominated by the selection rule of electron transition, Δl = ±1, where l is the orbital angular quantum number. We finally confirmed the existence of unpaired spins in excited zinc atoms by Electron Spin Resonance (ESR). This signal suggests that ion-recombination produces excited states of zinc that appear following ion-recombination and which are characterized by long lifetimes.
2. EXPERIMENTAL
2.1. Experimental system All experimental procedures were conducted in a vacuum. The vacuum system consisted of conventional equipment including a turbo molecular pump, in which ultimate pressure was 10-5 Pa order. Figure 1 provides a schematic illustration of incident electrons, and substrate and zinc ions. The electronic states on the substrates were controlled by the energies of electron irradiation emitted from a cathode in an electron gun. The magnitude of electron emissions was adjusted by the filament current. The kinetic energy of incident electrons was controlled by a potential between the anode of gold thin film deposited around the area of sapphire substrate and the hot filament of cathode in an electron gun. The incident angle of electrons was 45o from the normal substrate surface. Zinc atoms were deposited from the effusion cell, in which the purity of zinc was 99.999%. The zinc atoms were deposited on the insulative area, which measured 6.5 mm in diameter at the center of the substrate.
After the anode potential was adjusted to an appropriate level, the first stage was designed to control the potential energy of the insulative area of substrate surface by irradiation of electrons. Electrification in this area is monitored by the transmission electron current measured as the anode current (Obara et al., 2000). This method is one application of “angle resolved transmission electron current spectroscopy” (Obara et al., 1999). After 10 hours from irradiation of the electrons, the electron current became stable at 0.1 μA. The goal of the next stage was to deposit zinc atoms on the substrate surface. The incident angle of the zinc atom beam coming from the effusion cell was held to normal on the substrate surface. As a guide, a typical deposition time of zinc is about 1000 seconds at 600o C in the effusion cell.
2.2. Formation of boundary conditions
The microscopic understanding of growth processes is due to two different concepts of movements: the individual movement of incident atoms and the movement of surface atom systems as a group. The Surface Phase is considered to be the region where the two concepts merge (Bird, 1995). A key to controlling the reaction processes in the Surface Phase is the electron states of the surface atom system. The electron states near Fermi energy are complex because the incident atoms in condensation processes are a mix of many electron states that form a new band (Jones et al., 1934). We adopted an approach to the area of the surface phase from the gas phase side, as shown in Figure 1, because it is easy to describe the movement of individual atoms and to make the image of collisions between Zn+ in the gas phase and Zn- in the surface phase. In controllable two-body collision processes, changing of spatial and temporal parameters is a fundamental viewpoint for the generation of new reaction fields. We proposed to decrease the spatial parameters of the reaction field to increase the acceleration of incident Zn+ just before collision. The magnitude of the acceleration of Zn+ dominated the interaction with electromagnetic waves in the ion-recombination process. It should be noted that an electromagnetic wave is transformed to interaction energy with electric dipole moments (Ni et al., 2010). As shown in Figure 1, the Sapphire substrate had a gold electrode for applying the bias voltage for incident electrons. Charged electrons on the insulative area form the negative field and the magnitude of the surface potential, eVB. This value was equal to the bias potential of the gold electrode. Charged electron density depends on the distance from the center of the circular substrate, and charged electron density near the edge of the circular area was much larger than that at the center of the substrate because of creating homogeneous potential of the substrate.
2.3. Reaction processes
In the Figure 1, Zn+ is controlled by the energy of reaction field and reach to Zn- on the substrate surface. In the early stages, the interaction of both ions is possible to describe as like the dynamic and electromagnetic model which is called direct collision, because the distances between both ions are long. The direct collision process is possible to transfer by high efficiency from total energy to inner energy (Kawazoe et al., 2005). If the distance between ions approaches at the atomic diameter level, the interelectronic interaction increases in the both ion. In this situation, the linear combination with wave function of Zn+ and Zn- make possible to formation of molecular orbital, which is represented by the following equation in a quantum dynamic manner.
3. RESULTS
3.1. X-ray diffraction
Figure 2 shows the energy dependence of X-ray diffraction intensities scattered from the zinc films deposited under electron irradiation with the energy, eVB. Strong diffuse scattering of Xrays was observed at inherent electron energies, 10 eV, 90 eV, 100 eV, and 230 eV, which corresponded to the electron binding energies, 3d(10 eV), 3p(90 eV), 3d+3p(100 eV), and 3p+3s(230 eV) of the zinc atoms. Peak profiles at 90 eV, 100 eV, and 230 eV broadened as electron energy increased.
4. CONCLUSION
4.1. Contribution of inner-core excitation The electron excitation process depends on the initial and the final states in ions. The initial electron states of both ions are [Ar]3d104s1 for Zn+ , and [Ar]3d104s 2 4p 1 for Zn- . The excitation model from the inner-core electron states to the 4s-state for Zn+ , and 4p-state for Zn-
The column marked with “--” has no transited ion state. The term “(Zn+ )*” means the existence of excitation from 3d-state to 4p- state in Zn+ . The column of “Transition probability” of each ion state is written by numeric “1” for possible cases or “0” for impossible scenarios. The column, “Product of transition probability,” means the product of two ions’ probabilities. For this reason, numeric “1” shows the strong intensity of diffuse scattering or Bragg reflection and both strong intensities, and “0” shows the weak intensities. The column, “Intensity of diffraction,” shows the intensities for diffuse scattering and Bragg reflection, in which characters “H” and “L” mean, respectively, High and Low intensities. The column, “Contribution of excitation,” indicates that the “Intensity of diffraction” is affected by excitation of either ion species. The double excitations at 100 eV and 230 eV showed very strong diffuse scattering and Bragg reflection intensity. In the 3 single excitations at 10 eV, 90 eV and 140 eV, both 90 eV and 140 eV showed completely different characteristics.
4.2. Condensation model From the discussions of subsections 3.2 and 4.1, authors of this research proposed a model for the condensation process due to the ion-recombination process, as shown in Figure 6. The boundary condition was in the space where Zn- is located in the surface phase and in the space where Zn+ was located in the gas phase above the surface phase. As shown in Figure 6(a), the excitation in Zn+ had an influence on the nearest neighbor, Zn- . However this excitation was not available to bonding to the Zn atom in the solid phase because of the long distance between Zn+ in the gas phase and Zn atoms in the solid phase. When the excitation at the Zn+ site, the bonding with the solid phase became weak. Therefore, Zn+ and Zn- have a broad distribution function of lattice spacing for Zn in solid phase, and strong diffuse scattering occur.
5. CONCLUSION
The quantum dynamic processes for the first step of the condensation process from gas phase to solid phase were investigated by using the ion-recombination process. The electron energy dependencies of the derived crystals showed very strong diffuse scattering at discreet energies, which corresponded to the binding energies of zinc atoms. Strong Bragg reflections were also observed at discreet energies. From the comparison between these two series of experimental data, we proposed a model for the excitation of ions in which the excitation in Zn+ located at the gas phase induces strong diffuse scattering while excitation in Zn- located at the surface phase induces the strong Bragg reflection. This model demonstrates that the inner-core excitation process occurs before the process of charge exchange. We also confirmed the characteristic transformation of zinc film from a metallic to an insulative quality.
6. ACKNOWLEDGEMENT The authors thank Professor Yosihiko Hatano of the Advanced Science Research Center of Japan Atomic Energy Agency, and Professor Noriaki Itho of Nagoya University for continuous encouragement and helpful discussions.
7. REFERENCES Bendavid, A., Martin, P. J., Takikawa, H., 2000. Deposition and Modification of Titanium Dioxide Thin Films by Filtered Arc Deposition. Thin Solid Films, Volume 360, pp. 241- 249. Bird, G. A., 1995. Molecular Gas Dynamics and the Direct Simulation of Gas Flows, Clarendon Press, Oxford Engineering Science Series 42. Ehrlich, G., Hudda, G., 1966. Atomic View of Structure Self Diffusion: Tungsten on Tungsten. Journal of Chemical Physics, Volume 44, pp. 1039-1049. Ernst, H. J., Charra. F., Douillard. L., 1998. Interband Electronic Excitation-Assisted AtomicScale Restructuring of Metal Surfaces by Nanosecond Pulsed Laser Light. Science, Volume 279, pp. 679-681. Haigh, C. W., 1995. The Theory of Atomic Spectroscopy; j-j Coupling, Intermediate Coupling, and Configuration Interaction. Journal of Chemical Education, Volume 72, pp. 206. Hatano, Y., Mozumber, A., 2004. Charged Particle and Photon Interaction with Matter. New York (ISBN: 0-8247-4623-6). Herzberg, G., 1944. Atomic Spectra and Atomic Structure, Inc. New York, 2nd Ed, pp. 229-230. Itoh, N., Stoneham, A. M., 2000. Materials Modification by Electronic Excitation. Cambridge University Press, illustrated edition. Hay, P. J., Dunning. T. H, 1976. Electronic State of Zn2 Ab Initio Calculations of a prototype for Hg2. Journal of Chemical Physics, Volume 65, Number 7, pp. 2679-2685. Jones, H., Mott, N. F., Skinner, A., 1934. Theory of the Form of the X-Ray Emission Bands of Metals. Physical Review Letters, Volume 45, pp. 379-384. Kawazoe, T., Kobayashi, K., Otsu, M., 2005. Investigation and Development of Optical Nearfield Interaction between Nano-materials. Solid State Physics, Volume 40, Number 4, pp. 227-238. Ni, K. K., Ospelkaus, S., Wang, D., Quéméner, G., Neyenhuis, B., M.H.G. de Miranda., Bohn, J. L., Ye, J., Jin, D. S., 2010. Dipolar Collisions of Polar Molecules in the Quantum Regime. Nature, Volume 464, pp. 1324-1328. Obara, K., Muroya, K., Eguchi, K., Panli, Y., 2000. Angle Dependence of Transmission Probability of Incident Electrons into Thin Oxide Film and Noise Spectra. Thin Solid Films, Volume 375, pp. 275-279. Obara, K., Chiba, K., Nagano, O., Panli, Y., 1999. Monitoring the Surface Electronic States of Crystals in Vapor-Phase Growth Processes Under Magnetic Field. Journal of Crystal Growth, Volume 198/199, pp. 894-899. Ralchenko, Yu., Jou, F.-C., Kelleher, D.E., Kramida, A.E., Musgrove, A., Reader, J., Wiese, W.L., Olsen, K., 2007. NIST Atomic Energy Levels Bibliographic Database for Zn II, NIST Atomic Spectra Database, Version 3.1.2. National Institute of Standards and Technology Physical Laboratory, Available at: Xing, D., Ueda, K., Takuma, H., 1994. Electron Beam Excitation of Zn2 Excimer. Japanese Journal of Applied Physics, Volume 33, Number 12A, pp. 1676-1679
Example English Dialogue about Chemistry
Corrosive"
Teacher : Good Afternoon Class
Students : Good Afternoon ma'am
Teacher : Well, Can you guess what the stuff I bring?
Students : No ma'am, We don't know
Teacher : It's call hydrocloric acid solution
Students : Ohh
Teacher : Does anybody know the characteristic about hydrocloric acid solution from the way you see it?
Amel : I know
Teacher : Yes please
Amel : It has clear color ma'am
Teacher : exactly, anybody else? yes please
Rika : hydrocloric acid solution is a strong acid ma'am
Teacher : That's right!
Oni : But ma'am, why hydrocloric acid solution it strong acid?
Teacher : Nice question! well that's because hydrocloric acid solution has mixed by 2 elements, which is hydrogen and cl have strong ion bond, so that's can make a strong power to create a strong bond. Here do you see this symbol?
Students : Yes, we are
Teacher : So anybody can analyze the meaning of this symbol?
Rika : Can I ma'am?
Teacher : Yes please
Rika : That's symbol has mean corrosive. the chemical material can destructive life tissue, and then can make irritation on the skin. we can feel itchy because of that and our skin will peel
Teacher : Yeah! that's exactly what you say. Now we will to prove that hydrocloric acid solution is corrosive. Do you guys bring what I command last week?
Student : Yes ma'am
Teacher : Bring it here please
Amel : Here you are
Teacher : Well, you guys can take a look what I will doing, so what will happen if I trying to drop the solution on the steroform?
Oni : Woahh awasome... the steroform is melting
Amel : It's Amazing
Teacher : So you see it? it's melting right? this experiment has prove one of the hydrocloric acid solution characteristic, so what is the conclusion about this experiment?
Oni : So the conclusion is hydrocloric acid solution is a strong acid, and it can separate in the water, hydrocloric acid solution is made by covalent bond between H and Cl . And it can make the steroform melt, uhh I mean like it has corrosive characteristic
Teacher : Yeah that's right. that is the conclusion about hydrocloric acid solution, okay I think it's enough, I hope you learn more about this lesson, see you next week.
Cause and Effect
Chemistry is the science of dealing with the compounds, elements, and molecular structure of matter. Essentially, chemistry is the science of examining substances and objects to find out what they're made of and how the react to different conditions.
A cause-effect relationship is a relationship in which one event (the cause) makes another event happen (the effect). One cause can have several effects. For example, let's say you were conducting an experiment using regular high school students with no athletic ability. The purpose of our experiment is to see if becoming an all-star athlete would increase their attractiveness and popularity ratings among other high school students.
Suppose that your results showed that not only did the students view the all-star athletes as more attractive and popular, but the self-confidence of the athletes also improved.The key principle of establishing cause and effect is proving that the effects seen in the experiment happened after the cause.
Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products. An arrow is drawn between the reactants and products to indicate the direction of the chemical reaction, though a chemical reaction is not always a "one-way street," as we'll explore further in the next section.
For example, the reaction for breakdown of hydrogen peroxide (\text{H}_{2}H2H, start subscript, 2, end subscript\text{O}_{2}O2O, start subscript, 2, end subscript) into water and oxygen can be written as:
2 \text{H}_{2}2H22, H, start subscript, 2, end subscript\text{O}_{2} \text{(hydrogen peroxide)}O2(hydrogen peroxide)O, start subscript, 2, end subscript, left parenthesis, h, y, d, r, o, g, e, n, space, p, e, r, o, x, i, d, e, right parenthesis \rightarrow→right arrow 2\text{H}_{2}\text O \text{(water)}2H2O(water)2, H, start subscript, 2, end subscript, O, left parenthesis, w, a, t, e, r, right parenthesis + \text{O}_{2}\text{(oxygen)}O2(oxygen)O, start subscript, 2, end subscript, left parenthesis, o, x, y, g, e, n, right parenthesis
In this example hydrogen peroxide is our reactant, and it gets broken down into water and oxygen, our products. The atoms that started out in hydrogen peroxide molecules are rearranged to form water molecules (\text{H}_{2}\text OH2OH, start subscript, 2, end subscript, O) and oxygen molecules (\text O_2O2O, start subscript, 2, end subscript).
You may have noticed extra numbers in the chemical equation above: the 222s in front of hydrogen peroxide and water. These numbers are called coefficients, and they tell us how many of each molecule participate in the reaction. They must be included in order to make our equation balanced, meaning that the number of atoms of each element is the same on the two sides of the equation.
Equations must be balanced to reflect the law of conservation of matter, which states that no atoms are created or destroyed over the course of a normal chemical reaction. You can learn more about balancing reactions in the balancing chemical equations tutorial.
The causes of chemical reactions:
1. Occurs due to burning.
2. Occurs due to mixing of substances.
3. Occurs due to the flow of electricity.
The chemical reaction equation is written as follows:
A and B : reactant
C and D : reaction product.
In the reaction equation there is a symbol of the form of substance: s (solid), aq (aqueous), l (liquid) and g (gas).
The effect of chemical reactions
The formation of gas bubbles.
Gases produced in chemical reactions sometimes cause bubbles to form
Formation of Sludge
Color Changes Occurred
Temperature Changes
Lighting
Volume Changes Occurred
Conductivity change
Odor change occurred
LESSON PLAN (RPP) Of Entalphy On Curriculum 2013
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Education units
Subjects
Class / semesters
Subject matter
Time Allocation
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: High School
: Chemistry
: X / I
: Reaction enthalpy
changes
: 4 hours / week
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KI 1
KI 2
KI 3
KI 4
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:Appreciate and practice the teachings of their religion
: Appreciate and practice honest behavior, discipline, responsibility,
caring (gotong royong, cooperation, tolerance, peace), polite, responsive and
pro-active and displayed as part of the solution to various problems in
interacting effectively with the social and natural environment as well as in
placing itself as a reflection of the nation in the association world.
: Understand, implement, analyze the factual knowledge, conceptual,
procedural based flavor ingintahunya about science, technology, art, culture,
and humanities with insights into humanity, nation, state, and
civilization-related causes of phenomena and events, as well as applying
procedural knowledge in the field of study specific according to their
talents and interests to solve the problem,
: Processing, reasoning, and menyaji in the realm of the concrete and
the abstract realm associated with the development of learned in school
independently, and able to use the method according to the rules of science.
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1.1.
1.2
1.3.
1.4.
1.5.
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Recognizing
the regularity of hydrocarbon properties, thermochemical, lajureaksi,
chemical equilibrium, solutions and colloids as a manifestation of the
greatness of Almighty God and the knowledge of their regularity as a result
of human creative thinking tentative truth.
Grateful for Indonesia's natural wealth in the form of
petroleum, coal and natural gas as well as various other mineral as a gift of
God Almighty and can be used for the welfare of the people of Indonesia
Shows the behavior of scientific (curious, disciplined, honest,
objective, open, able to distinguish between fact and opinion, tenacious,
thorough, responsible, critical, creative, innovative, democratic,
communicative) in designing and conducting experiments and discussions are
embodied in everyday attitude.
Menunjukkanperilaku cooperation, courtesy, tolerance, cintadamai and care
for the environment and saving in the use of natural resources.
Exhibit behaviors
responsive and pro-active as well as wise as a manifestation of the ability
to solve problems and make decisions
Designing,
conducting, and concluding, and presents the results of experimental
determination DH
reaction.
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1.
Media
2.
material
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:
Power point
: Handbook of Chemistry vol 1 and supplementary
relevant
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Details of activities
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Time
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PRELIMINARY
1.
Students answered
greeting teachers, pray, and conditioning themselves ready to learn.
2.
Students and teachers
asked responsibilities pertaining to the universe.
3.
Students listened to
an explanation of the purpose of learning and mastering the benefits of
learning materials.
4.
Students listened
scope of learning materials are delivered properly.
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20 minutes
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CORE
ACTIVITIES
Observe (Observing)
·
Gather
information by reading / hearing / watching / systems and the environment,
changes in temperature, the heat produced in the combustion of fuel, and the
impact of incomplete combustion of various fuels
Ask (Questioning)
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Asking
questions related to:
exothermic and
endothermic reactions in daily life, how to determine the reaction enthalpy
change
Gather data (Eksperimenting)
·
Discuss
the definition of the system and the environment
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Discussing
various changes in enthalpy
·
Designing
and presenting experimental design
- Determination of the enthalpy changes
calorimeter
-
Determination
Heat Fuel Combustion
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Conducting experiments, determine the enthalpy change of the calorimeter
and determining the heat of combustion of fuel
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Observe and record the results of the experiment
associate
(Associating)
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Analyze data to create charts and diagrams cycle level
·
Examines
the data to determine the price change in enthalpy (principle Black)
Communicating (Communicating)
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Report the results of the experiment using proper grammar.
·
Presenting the results of the experiment using proper grammar.
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70 Minutes
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COVER
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Students conclude the
materials that have been studied
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The student reflects
mastery of the material that has been studied by making notes mastery of the
material.
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Students do the
evaluation.
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10 minutes
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Knowing
Head of SMA Negeri 1 newyork
Drs. H. masagitusih B, M.Pd
NIP.
999999999999999999
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Subject teachers
karlina, S.Pd
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