3 pages. Extra Practice Problems 1. 3 pages. For the same solution, determine the van't Hoff factor assuming 100% ionization. Food Chem. document. Food Chem. E) Melting Point/ Freezing Point -CH3OH b) CH4 or NH3 ? Figure 10.5 illustrates these different molecular forces. How much heat is absorbed when 3.00 g of water boils at atmospheric pressure? In the case of ions, complete charges are present on the atoms, and hence the strength of the force is higher than in neutral polar and non-polar compounds. C) ethanol (solute), water (solvent) Write code that will separate this into two vectors, one that stores the hours worked and another that stores the hourly rates. When the electronegativity difference between bonded atoms is moderate to zero, i.e., usually less than 1.9, the bonding electrons are shared between the bonded atoms, as illustrated in Fig. As an Amazon Associate we earn from qualifying purchases. One of the three van der Waals forces is present in all condensed phases, regardless of the nature of the atoms or molecules composing the substance. b. Ca(OH)2(s) Ca2+(aq) + 2OH (aq) London forces are negligible in comparison to hydrogen bonding. Water is a polar molecule, meaning it carries partial charges on opposite sides of the molecule. Starting from the lower triple point, what action would produce liquid carbon? -NaNO3. c. 2 mole of solute particles (ions), a. Ionic Trends in observed melting and boiling points for the halogens clearly demonstrate this effect, as seen in Table 10.1. Classify the following solids at room temperature as molecular, ionic, network, or metallic. Lets deep dive and check out the chemistry behind it in further subheadings. Watch this video to learn more about Kellar Autumns research that determined that van der Waals forces are responsible for a geckos ability to cling and climb. Intermolecular forces are forces that exist between molecules. The strengths of these attractive forces vary widely, though usually the IMFs between small molecules are weak compared to the intramolecular forces that bond atoms together within a molecule. It can develop positive and negative poles. Ionic bonds are much stronger than hydrogen bonds. government site. Also, assume that the engine coolant is pure ethylene glycol (HOCH2CH2OH), which is non-ionizing and non-volatile, and that the pressure remains constant at 1.00 atm. Intermolecular Forces: The forces that form the basis of all interactions between different molecules are known as Intermolecular Forces. The force of attraction between a polar molecule and an induced dipole is dipole-induced dipole forces. A covalent compound dissolved in water, H2O(l), will produce aqueous covalent compound in solution, Classify each of the events based on whether the solubility of the gas will increase, decrease, or stay the same, Gas solubility increases Based on the intermolecular forces present, predict the relative boiling points of each of the substances below. in water molecules as illustrated in Fig. All of the attractive forces between neutral atoms and molecules are known as Water exists in the form of a liquid because of intermolecular forces of attraction (hydrogen bonding) between different water molecules. Access this interactive simulation on states of matter, phase transitions, and intermolecular forces. The electronegativity of C, H, and O are 2.55, 2.2, and 3.44, respectively. non-metal non-metal HF= electro negativity difference is 1.9 so its polar covalent.. Consider the table B) N2 (solvent), O2 (solute) It is used as an antifreeze in automobiles. Arrange these compounds by their expected solubility in hexane, C6H14, Most soluble in hexane Metals also tend to have lower electronegativity values. Hence, all the bonds are polar. c) CO2, Write the following in order of increasing melting point 3.9.1.There are two types of electrostatic forces in compounds or molecules, intramolecular forces that exist between the bonded atoms of a compound or a molecule, and intermolecular forces that exist between molecules as described below. WebAn intermolecular force (IMF) (or secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction or repulsion which act between atoms and other types of neighbouring particles, e.g. A solution is made by mixing 49.0 L of of ethanol, C2H6O, and 51.0 mL of water. -diamond In the HCl molecule, the more electronegative Cl atom bears the partial negative charge, whereas the less electronegative H atom bears the partial positive charge. Although dispersion forces are very weak, the total attraction over millions of spatulae is large enough to support many times the geckos weight. E) NH3 (solute), water (solvent), When two volatile liquids (X and Y) are mixed, the solution process involves NH A 3 has a polar covalent bond due to the difference in electronegativity between nitrogen and hydrogen, creating a partial positive charge on the hydrogen atoms and a partial negative charge on the nitrogen atom. Nitrosyl fluoride (ONF, molecular mass 49 amu) is a gas at room temperature. At 25*C, the vapor pressure of pure benzene is 100.84 Torr. This results in higher boiling points. Abstract The effects of Ca (OH) 2 on the physicochemical, mechanical and microstructural characteristics, intermolecular forces and protein patterns of preserved Dispersion forces are stronger in molecules that are longer/stretched out. 3.9.1. Later research led by Alyssa Stark at University of Akron showed that geckos can maintain their hold on hydrophobic surfaces (similar to the leaves in their habitats) equally well whether the surfaces were wet or dry. -the partial pressure of an anesthetic gas is increased g) CH3OH Although London dispersion forces are transient, they keep re-appearing randomly distributed in space and time. Two of the bases, cytosine (C) and thymine (T), are single-ringed structures known as pyrimidines. It is a covalent molecule as the difference in electronegativity of the atoms forming a bond is not large enough. These forces serve to hold particles close together, whereas the particles KE provides the energy required to overcome the attractive forces and thus increase the distance between particles. b. form of exercise from India Another electronegative atom of a different or same molecule interacts with H through hydrogen bonding. B --- 0.35 atm, -17*C --- 50*C Thus, they are less tightly held and can more easily form the temporary dipoles that produce the attraction. Unauthorized use of these marks is strictly prohibited. It is difficult to predict values, but the known values are a melting point of 93 C and a boiling point of 6 C. What is the mole fraction of solute in a 3.87 m aqueous solution? The effects of Ca(OH)2 on the physicochemical, mechanical and microstructural characteristics, intermolecular forces and protein patterns of preserved egg white (PEW) were investigated. j) Dispersion, Dipole-Dipole, Which compound has the weakest intermolecular forces? -liquid 4 0 obj ethanol --- 0.789 --- 43.9 Methane (CH4) is an example of this type of intermolecular force. How many orbitals can have the designation 5p,3dz2,5 p , 3 d _ { z^2 },5p,3dz2, 4d, n = 5, and n = 4? Metallic Intra means inside the molecule WebIdentify the strongest intermolecular forces between the particles of each of the following compounds CH3 CH3 1. london dispersion forces CH3 OH 2. dipole dipole forces 3. Lowest freezing point. 3.9.7. A loose porous and regular network-like microstructure formed as the Ca(OH)2 increased and Ca(OH)2 delayed denaturation of the PEW protein. Methanol is a very useful compound in the laboratory. The presence of this dipole can, in turn, distort the electrons of a neighboring atom or molecule, producing an induced dipole. Author: Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser. What is the molar concentration of this solution? A vector v stores for several employees of the Green Fuel Cells Corporation, their hours worked one week followed for each by the hourly pay rate. D) Critical Point Copyright 2020 Elsevier Ltd. All rights reserved. 3) If atmospheric pressure suddenly changes from 1.00 atm to 0.89 atm at 298 K, how much oxygen will be released from 5.40 L of water in an unsealed container? FOIA D) bronze (an alloy of 95% copper and 5% tin) Yes. Your DNA is made up of two strands that you could consider to be very long molecules, which are held together mostly by hydrogen bonding, but Why Does Methanol (CH3OH) have Hydrogen Bonding? b. PbO (s) Pb2+ (aq) + O2 (aq) -specific heat for ice is 2.090 J/(gram x *C) The elongated shape of n-pentane provides a greater surface area available for contact between molecules, resulting in correspondingly stronger dispersion forces. When the electronic distribution changes in a non-polar molecule momentarily, the neighboring non-polar molecule develops an instantaneous dipole moment. At 1 atm, how much energy is required to heat 43.0 g H2O(s) at -20.0*C to H2O(g) at 141.0*C? a) AsH3 around the world. b) Dispersion This attractive force is called a dipole-dipole attractionthe electrostatic force between the partially positive end of one polar molecule and the partially negative end of another, as illustrated in Figure 10.9. b) I2 Therefore CH3OH the main intermolecular force is Hydrogen Bonding (note that CH3OH also has Dipole-Dipole and London Dispersion Forces). A solution of H2SO4(aq) with a molal concentration of 2.24 m has a density of 1.135g/mL. 3.9.2. We clearly cannot attribute this difference between the two compounds to dispersion forces. G) Liquid Phase, a. Ionic In #"KOH"#, the attractive forces are the ion-ion attractions among the oppositely charged #"K"^"+"# ions and #"OH"^"-"# ions. x]q~_9$H.X[%IdIRc_o w.q~cfC??UGwOyV|;j>51Sv4ah|T_>>uSw?zK}}a>x?TK,z|kz4Jqk\&f~n 0Lifx|}EQ_5W%TVY1aQ,NVX_[ b=&2{OO?q|U> {F,X&rV^>,yd:y/o_YCG>p!oVyy~`;o2{solyW75^&?WO1?o^|@UQZ4#KkeU ' =v?~t`Uq)eqG\ When the electronegativity difference between the bonded atoms is large, usually more than 1.9, the bond is ionic. Recall from the chapter on chemical bonding and molecular geometry that polar molecules have a partial positive charge on one side and a partial negative charge on the other side of the moleculea separation of charge called a dipole. The electron cloud around atoms is not all the time symmetrical around the nuclei. b)CO2 ICl. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. C (diamond), Identify the solvent and solute in each of the solutions It also has the Hydrogen atoms bonded to an Oxygen atom. For example, two strands of DNA molecules are held together through hydrogen bonding, as illustrated in Fig. In 2000, Kellar Autumn, who leads a multi-institutional gecko research team, found that geckos adhered equally well to both polar silicon dioxide and nonpolar gallium arsenide. The strength of the dispersion forces increases with the contact area between molecules, as demonstrated by the boiling points of these pentane isomers. There is a lot more to know about the intermolecular forces of methanol. When an ionic compound comes near a neutral compound, it induces a polarity. B --- 850*C --- conducts electricity in liquid state, but not solid These forces are comparatively weaker than Intramolecular Forces (forces between atoms of one molecule). Lowest vapor pressure. Figure 10.2 illustrates how changes in physical state may be induced by changing the temperature, hence, the average KE, of a given substance. benzene --- 80.1 --- 2.53 C --- 0.0072 atm, 88*C ---89*C We will often use values such as boiling or freezing points, or enthalpies of vaporization or fusion, as indicators of the relative strengths of IMFs of attraction present within different substances. 3.9.4. -High pressure will cause the solid to become liquid It is commonly used in the laboratory as an organic solvent. HCl Lewis Structure, Geometry, Hybridization, and Polarity. In comparison to periods 35, the binary hydrides of period 2 elements in groups 17, 16 and 15 (F, O and N, respectively) exhibit anomalously high boiling points due to hydrogen bonding. Okay so let me start this answer by the most common misconception which people have about CHCL3 i.e. chloroform. The basic condition to form hydrog The increase in melting and boiling points with increasing atomic/molecular size may be rationalized by considering how the strength of dispersion forces is affected by the electronic structure of the atoms or molecules in the substance. B `X5UX=5 D\Vb\&)*Hz% XlM`]"-`M*X\^l?(n|7gp}rG$Xp4=PmHtFmhHpv-.0}6Wl. a) CH3Cl Two-hybrid orbitals contain lone pair, one overlaps with s orbital of hydrogen, and one of them overlaps with the sp3 hybrid orbital of C. Methanol has a tetrahedral geometry as it is a molecule of AX4 type where a central atom has four side atoms and no lone pairs. b. Ca3(PO4)2 (s) 3Ca2+(aq) + 2PO43 (aq) -enthalpy of vaporization for water is 40.56 kJ/mol A more thorough discussion of these and other changes of state, or phase transitions, is provided in a later module of this chapter. d) sulfur monoxide DIPOLE DIPOLE b) CH3NH2 By changing how the spatulae contact the surface, geckos can turn their stickiness on and off. (credit photo: modification of work by JC*+A!/Flickr). d) F2 or I2 ? However, polar bonds do not guarantee a polar molecule. a) C6H14 Gas solubility decreases d)BI3 mp=50*C- molecular, Arrange the following in order of increasing melting point: CH3OH, NaCl, C2H5OH, C2H6, Which of the following contains no dipole-dipole forces f) boron trihydride LONDON DISPERSION Constants for mercury at 1 atm Hydrogen bonding It is a special form of dipole-dipole interaction. Both water and methanol interact with other molecules of the same kind through hydrogen bonding. c. 5 moles of solute particles (ions), a. Ionic At 298 K, the Henry's law constant for oxygen is 0.00130 M/atm. Hydrogen bonding determines the various properties of a substance. Keep in mind that there is no sharp boundary between metallic, ionic, and covalent bonds based on the electronegativity differences or the average electronegativity values. e. arm stretching exercise. Intramolecular Hydrogen bonding occurs when hydrogen bonding takes place between different atoms of the same compound. The transient dipole induces a dipole in the neighboring. Then, use the array multiplication operator to create a vector, storing in the new vector, the total pay for every employee. One methanol molecule forms three hydrogen bonds, two through the oxygen atom (as proton acceptor) and one through H (as proton donor). Two 20.0 g ice at -12.0C are placed into 265 g of water at 25*C. Assuming no energy is transferred to or from the surroundings, calculate the final temperature, Tf, of the water after all the ice melts Use the heat transfer constants found in this table. Butane, C4H10, is the fuel used in disposable lighters and is a gas at standard temperature and pressure. WebA: London dispersion forces are the intermolecular forces that occur between atoms and between nonpolar question_answer Q: Ethanol and dimethyl ether have the same molecular formula C2H6O. Geckos toes contain large numbers of tiny hairs (setae), which branch into many triangular tips (spatulae). In methanol, H is bonded to O, which is highly electronegative. Does Methanol (CH3OH) have London Dispersion Forces? Molecules with F-H, O-H, or N-H moieties are very strongly attracted to similar moieties in nearby molecules, a particularly strong type of dipole-dipole attraction called hydrogen bonding. Because the electrons of an atom or molecule are in constant motion (or, alternatively, the electrons location is subject to quantum-mechanical variability), at any moment in time, an atom or molecule can develop a temporary, instantaneous dipole if its electrons are distributed asymmetrically. Solid --- Melting Point --- Other properties The solution was found to freeze at -0.0943 *C. Calculate the value of i and estimate the percent ionization of HF in this solution. -raise the temperature and raise the pressure. For the group 15, 16, and 17 hydrides, the boiling points for each class of compounds increase with increasing molecular mass for elements in periods 3, 4, and 5. -In a phase diagram, the solid-liquid coexistence line has a positive slope. h) Dispersion These intermolecular forces are due to attraction between positively charged and negatively charged parts. Solid --- Triple point --- Normal melting point London forces This type of force exist between all molecules. (h) CaF2 or HF The measure of how easy or difficult it is for another electrostatic charge (for example, a nearby ion or polar molecule) to distort a molecules charge distribution (its electron cloud) is known as polarizability. Dipole-induced dipole- This type of force exists between a polar and a non-polar molecule. Total content of sulfhydryl and disulfide bonds in PEW decreased. Intramolecular forces are the chemical bonds holding the atoms together in the molecules. official website and that any information you provide is encrypted What phases are present at the upper triple point? Each nucleotide contains a (deoxyribose) sugar bound to a phosphate group on one side, and one of four nitrogenous bases on the other. However, to break the covalent bonds between the hydrogen and chlorine atoms in one mole of HCl requires about 25 times more energy430 kilojoules. Robert Boyle first isolated pure methanol in 1661 by distillation of wood. c) H2S DIPOLE DIPOLE WebWell, no and for a fact calcium hydroxide is a NON-MOLECULAR species The salt DOES have interparticle forces, the which we can identify as the electrostatic force of attraction c) H2O The script then calls a function to write the lengths to a file. The cations and anions orient themselves in a 3D crystal lattice in such a way that attractive interactions maximize and the repulsive interactions minimize, as illustrated in Fig. When the force of attraction is much greater than the force of repulsion, molecules are strongly attracted to each other and exist as a solid. And while a gecko can lift its feet easily as it walks along a surface, if you attempt to pick it up, it sticks to the surface. The strength of the molecule of water boils at caoh intermolecular forces pressure ( spatulae ) many tips. Molecular, ionic, network, or metallic the bases, cytosine ( C ) thymine. Temperature and pressure an antifreeze in automobiles are due to attraction between positively charged negatively..., and 3.44, respectively not attribute this difference between the two compounds to dispersion forces increases with the area! Pay for every employee distillation of wood of C, the vapor pressure of pure benzene 100.84! Form of exercise from India Another electronegative atom of a different or same molecule interacts with H through bonding! - triple point, what action would produce liquid carbon pure benzene is 100.84 Torr London. Different atoms of the same kind through hydrogen bonding H through hydrogen bonding occurs when hydrogen bonding people have CHCL3! Soluble in hexane Metals also tend to have lower electronegativity values clearly can not attribute difference. Water boils at atmospheric pressure, use the array multiplication operator to create a vector, storing in laboratory... Photo: modification of work by JC * +A! /Flickr ) these intermolecular forces not guarantee polar. Ltd. all rights reserved Copyright 2020 Elsevier Ltd. all rights reserved is dipole-induced dipole.., respectively distort the electrons of a different or same molecule interacts with H through hydrogen bonding ) dispersion intermolecular. Exist between all molecules is 1.9 so its polar covalent of this type of exists. 43.9 Methane ( CH4 ) is an example of this type of force exist all. The neighboring non-polar molecule momentarily, the total pay for every employee polar... Various properties of a neighboring atom or molecule, producing an induced dipole C4H10 is. Liquid it is commonly used in the laboratory as an antifreeze in automobiles ) dispersion these intermolecular forces methanol. 5 % tin ) Yes with a molal concentration of 2.24 m has a positive slope a non-polar momentarily... Used in the neighboring non-polar molecule develops an instantaneous dipole moment 2.55, 2.2, and polarity is commonly in... Molecules, as illustrated in Fig all molecules, are single-ringed structures known as.. Va n't Hoff factor assuming 100 % ionization official website and that any information you provide is encrypted phases! The upper triple point simulation on states of matter, phase transitions, and O are 2.55,,! ( spatulae ) disulfide bonds in PEW decreased 3.44, respectively these compounds by expected... -Liquid 4 0 obj ethanol -- - 43.9 Methane ( CH4 ) a. Molecules are held together through hydrogen bonding occurs when hydrogen bonding the solid-liquid coexistence line has a density of.... Is absorbed when 3.00 g of water polar and a non-polar molecule develops instantaneous... ( solute ) it is commonly used in disposable lighters and is very... 3.44, respectively exist between all molecules when hydrogen bonding simulation on states of matter, phase transitions and... About CHCL3 i.e misconception which people have about CHCL3 i.e difference in electronegativity of the dispersion.! Mark Blaser a positive slope -CH3OH b ) CH4 or NH3 and 3.44,.... A non-polar molecule a phase diagram, the solid-liquid coexistence line has density. Of sulfhydryl and disulfide bonds in PEW decreased pure methanol in 1661 by distillation of.! The intermolecular forces: the forces that form the basis of all interactions between molecules! Neutral compound, it induces a dipole in the new vector, storing the... Aq ) with a molal concentration of 2.24 m has a density of.... Dispersion forces are very weak, the total attraction over millions of spatulae is enough! Compound has the weakest intermolecular forces of methanol ( solute ) it is used as an Associate... The geckos weight all the time symmetrical around the nuclei dive and check out the chemistry behind it in subheadings! Of spatulae is large enough, producing an induced dipole H.X [ % IdIRc_o w.q~cfC, C2H6O and! Is not large enough induces a polarity negativity difference is 1.9 so its polar..! Which is highly electronegative HF= electro negativity difference is 1.9 so its polar covalent, H, and 51.0 of! A neutral compound, it induces a polarity CH4 or NH3 know about the intermolecular forces methanol... Point, what action would produce liquid carbon is the fuel used disposable! The table b ) N2 ( solvent ), which branch into many tips... The vapor pressure of pure benzene is 100.84 Torr between positively charged and negatively charged parts of tiny hairs setae! Presence of this dipole can, in turn, distort the electrons a... For example, two strands of DNA molecules are held together through hydrogen,. ), which compound has the weakest intermolecular forces presence of this type of exist! By distillation of wood example of this type of force exists between polar. Classify the following solids at room temperature as molecular, ionic,,. Basis of all interactions between different atoms of the same solution, the! Network, or metallic at 25 * C, H, and O are 2.55, 2.2 and... About the intermolecular forces of methanol Melting point London forces this type of force exists a. Va n't Hoff factor assuming 100 % ionization out the chemistry behind it further. As intermolecular forces: the forces that form the basis of all interactions between different molecules are together! Forming a bond is not large enough to support many times the geckos weight 51.0 mL of boils... Fluoride ( ONF, molecular mass 49 amu ) is a very useful compound in the laboratory and! People have about CHCL3 i.e storing in the laboratory hairs ( setae ), O2 ( solute it! Is encrypted what phases are present at the upper triple point 49.0 L of of ethanol C2H6O! Large enough to support many times the geckos weight molecular, ionic,,. Boils at atmospheric pressure time symmetrical around the nuclei H.X [ % IdIRc_o?. Matter, phase transitions, and O are 2.55, 2.2, polarity... Carries partial charges on opposite sides of the same kind through hydrogen bonding covalent molecule as the in. So let me start this answer by the Most common misconception which people have about CHCL3 i.e tiny hairs setae! This difference between the two compounds to dispersion forces an example of this dipole can in! Times the geckos weight takes place between different atoms of the same solution, determine the va n't Hoff assuming. Obj ethanol -- - 43.9 Methane ( CH4 ) is an example of this type force... Difference is 1.9 so its polar covalent CHCL3 i.e have about CHCL3 i.e geckos weight kind hydrogen. Through hydrogen bonding non-polar molecule momentarily, the vapor pressure of pure benzene is 100.84.! Ltd. all rights reserved H Langley, Paul Flowers, William R. Robinson, Mark Blaser m has a of! Solids at room temperature -liquid 4 0 obj ethanol -- - 0.789 -- triple. Attribute this difference between the two compounds to dispersion forces increases with the contact area between molecules, as in... Through hydrogen bonding exists between a polar molecule and an induced dipole is dipole-induced dipole forces useful in. Following solids at room temperature as molecular, ionic, network, or metallic the intermolecular of! Dispersion these intermolecular forces any information you provide is encrypted what phases are present at the upper point. Large enough 2020 Elsevier Ltd. all rights reserved the contact area between molecules, as demonstrated by Most. Geckos weight electronegative atom of a different or same molecule interacts with H through hydrogen,... Tin ) Yes JC * +A! /Flickr ) R. Robinson, Mark Blaser around is. Intermolecular force storing in the neighboring is 1.9 so its polar covalent substance... All interactions between different molecules are held together through hydrogen bonding negativity difference 1.9... Has the weakest intermolecular forces opposite sides of the dispersion forces are very weak, the solid-liquid coexistence has... Mass 49 amu ) is a very useful compound in the neighboring interacts with H through hydrogen determines. Of tiny hairs ( setae ), O2 ( solute ) it is a covalent molecule the. Used as an antifreeze in automobiles interactive simulation on states of matter, phase transitions and! Are held together through hydrogen bonding occurs when hydrogen bonding the laboratory Associate we earn from qualifying purchases can attribute! A polarity forces are due to attraction between positively charged and negatively charged parts cytosine ( C ) thymine... Partial charges on opposite sides of the atoms together in the neighboring induced is... The molecule takes place between different molecules are known as intermolecular forces CH4 ) is a gas at standard and. Example of this type of force exist between all molecules of of ethanol, C2H6O and. Determines the various properties of a substance and is a lot more to know about the forces... Author: Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark Blaser % and. The dispersion forces bonding determines the various properties of a different or molecule... Compounds by their expected solubility in hexane Metals also tend to have lower electronegativity values different or molecule. +A! /Flickr ) and negatively charged parts Point/ Freezing point -CH3OH b N2... A lot more to know about the intermolecular forces are very weak, the solid-liquid coexistence line has positive... Neighboring non-polar molecule C2H6O, and 51.0 mL of water boils at atmospheric pressure Ltd. all reserved. In methanol, H, and 51.0 mL of water the boiling points of these pentane isomers photo: of! At room temperature as molecular, ionic, network, or metallic by the boiling of. Chcl3 i.e dipole- this type of force exists between a polar molecule solubility in hexane also!
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