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Why Does Glucose Not Dissociate In Water

7.5: Aqueous Solutions

7.5: Aqueous Solutions

Define a solution and describe the parts of a solution. Describe how an aqueous solution is formed from both ionic compounds and molecular compounds. Recognize that some compounds are insoluble in water. Describe the differences among strong electrolytes, weak electrolytes, and nonelectrolytes. When one substance dissolves into another, a solution is formed. Asolutionis a homogenous mixture consisting of a solute dissolved into a solvent.Thesoluteis the substance that is being dissolved,while thesolventis the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents. In this chapter, we will focus on solution where the solvent is water. Anaqueous solutionis water that contains one or more dissolved substance.The dissolved substances in an aqueous solution may be solids, gases, or other liquids. In order to be a true solution, a mixture must be stable. When sugar is fully dissolved into water, it can stand for an indefinite amount of time, and the sugar will not settle out of the solution. Further, if the sugar-water solution is passed through a filter, it will remain with the water. This is because the dissolved particles in a solution are very small, usually less than \(1 \: \text{nm}\) in diameter. Solute particles can be atoms, ions, or molecules, depending on the type of substance that has been dissolved. Figure \(\PageIndex{1}\):When a colored solution is passed through a filter, the entire solution, both solute and solvent, pass through unchanged. Water typically dissolves most ionic compounds and polar molecules. Nonpolar molecules, such as those found in grease or oil, do not dissolve in water. We will first examine the process that occurs when an ionic compound, such as table salt (sodium chloride), dissolves in wat Continue reading >>

Solubility And Complex-ion Equilibria

Solubility And Complex-ion Equilibria

The sugar we use to sweeten coffee or tea is a molecular solid, in which theindividual molecules are held together by relatively weak intermolecular forces. Whensugar dissolves in water, the weak bonds between the individual sucrose molecules arebroken, and these C12H22O11 molecules are released intosolution. It takes energy to break the bonds between the C12H22O11molecules in sucrose. It also takes energy to break the hydrogen bonds in water that mustbe disrupted to insert one of these sucrose molecules into solution. Sugar dissolves inwater because energy is given off when the slightly polar sucrose molecules formintermolecular bonds with the polar water molecules. The weak bonds that form between thesolute and the solvent compensate for the energy needed to disrupt the structure of boththe pure solute and the solvent. In the case of sugar and water, this process works sowell that up to 1800 grams of sucrose can dissolve in a liter of water. Ionic solids (or salts) contain positive and negative ions, which are heldtogether by the strong force of attraction between particles with opposite charges. Whenone of these solids dissolves in water, the ions that form the solid are released intosolution, where they become associated with the polar solvent molecules. Eventually, the Na+ and Cl- ion concentrations become largeenough that the rate at which precipitation occurs exactly balances the rate at which NaCldissolves. Once that happens, there is no change in the concentration of these ions withtime and the reaction is at equilibrium. When this system reaches equilibrium it is calleda saturated solution, because it contains the maximum concentration of ions thatcan exist in equilibrium with the solid salt. The amount of salt that must be added to agiven volume of solvent t Continue reading >>

Chemistry Ii: Water And Organic Molecules

Chemistry Ii: Water And Organic Molecules

Table of Contents It can be quite correctly argued that life exists on Earth because of the abundant liquid water. Other planets have water, but they either have it as a gas (Venus) or ice (Mars). This relationship is shown in Figure 1. Recent studies of Mars reveal the presence sometime in the past of running fluid, possibly water. The chemical nature of water is thus one we must examine as it permeates living systems: water is a universal solvent, and can be too much of a good thing for some cells to deal with. Figure 1. Water can exist in all three states of matter on Earth, while only in one state on our two nearest neighboring planets. The above graph is from Water is polar covalently bonded within the molecule. This unequal sharing of the electrons results in a slightly positive and a slightly negative side of the molecule. Other molecules, such as Ethane, are nonpolar, having neither a positive nor a negative side, as shown in Figure 2. Figure 2. The difference between a polar (water) and nonpolar (ethane) molecule is due to the unequal sharing of electrons within the polar molecule. Nonpolar molecules have electrons equally shared within their covalent bonds. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission. These link up by the hydrogen bond discussed earlier. Consequently, water has a great interconnectivity of individual molecules, which is caused by the individually weak hydrogen bonds, shown in Figure 3, that can be quite strong when taken by the billions. Figure 3. Formation of a hydrogen bond between the hydrogen side of one water molecule and the oxygen side of another water molecule. Image from Purves et al., Life: The Science of Biology, Continue reading >>

Tutorial Notes For Help Session On Osmosis

Tutorial Notes For Help Session On Osmosis

Will water move? Which way does the water move? Is the outside solution hypo-osmotic, hyper-osmotic, or iso-osmotic to the inside solution? Answers/Explanations Remember that we must consider the movement of water separately from solute (consider the "solution" in its component parts) Yes, there will be a net movement of water. Water moves INTO the cell SYMBOL 239 \f "Wingdings" The side with the higher concentration of solute has the lower concentration of free, diffusable water. So water will move from the 0.1 M glucose solution into the 0.25 M glucose solution. Remember thermodynamics: The system will move spontaneously to a situation of lower energy ---- the lowest energy situation is for the concentration to be equal on both sides of the membrane. As water moves in the interior solution becomes more dilute --- closer to the outside solution. Once the two concentrations equal each other, the system is at equilibrium (no net water movement across the membrane). The movement of water into the 0.25 M glucose is spontaneous; it requires no input of energy or pump. The outside solution is hypo-osmotic to the inside solution. Look at the solute concentrations when you determine the term to use. The outside solution has a LOWER solute concentration so is HYPO (under) in relation to the inside solution. Hyper is "over, above" and iso is "same, equal". PROBLEM/QUESTIONS 2. Osmosis situation with two different solutes, requiring some unit conversion. The semi-permeable membrane in this example will not allow sugars to pass. Does it matter which solute is on each side when considering osmosis? Which way will the water move? Is the outside solution hypo-osmotic, hyper-osmotic, or iso-osmotic to the inside solution? ------------------------------------------------------- 3. Osmo Continue reading >>

Redox - If A Sugar Is Nonreducing, Does That Mean It Doesn't Ionize In Water? - Chemistry Stack Exchange

Redox - If A Sugar Is Nonreducing, Does That Mean It Doesn't Ionize In Water? - Chemistry Stack Exchange

If a sugar is nonreducing, does that mean it doesn't ionize in water? I'm thinking of sucrose, which I learned is nonreducing , what I take to mean it doesn't accept/take electrons from the surrounding solution. Does this also mean that it doesn't ionize and thus has a Van't Hoff factor ( i ) of 1? I believe the confusion lies with the term Reducing sugar . From my perspective sucrose is not an ionic compound, it is covalently bonded. I believe that this should indicate to you that it does not "ionize" or the term that I was taught "dissociate" since it has nothing to dissociate from. "The van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved, and the concentration of a substance as calculated from its mass." Since it does not "dissociate," I would say that the answer is no, it does not "ionize," and therefore has a Van't Hoff factor of 1 when mixed with pure water. Like anything with electrons, they can be lost. This takes place in our bodies through more complicated reactions than I understand completely. I believe however, according to wikipedia, that sucrose has a Glycosidic bond which when broken, will separate sucrose into smaller sugars, if this takes place in your solution then I believe it will have a Van't Hoff factor > 1. accept an electron. Actually, in the case of a reducing sugar, it donates an electron. When it does so, it is oxidised. But that doesn't mean that it ionizes in water! When you keep a reducing sugar in the presence of an oxidising agent, the electron is transferred over to the agent, reducing it. The sugar may form an ion, or it may form a carboxylic acid (depending on the medium). The electron is fuelling the reduction half reaction of the oxidising agent we have used. If we Continue reading >>

Why Does Salt (nacl) That Has Dissociated In Water Make The Solution Salty, Even Though They Have Become Na Ions And Cl Ions? - Askscience

Why Does Salt (nacl) That Has Dissociated In Water Make The Solution Salty, Even Though They Have Become Na Ions And Cl Ions? - Askscience

Why does salt (NaCl) that has dissociated in water make the solution salty, even though they have become Na ions and Cl ions? Glucose, does not dissociate in water, and so I think I can understand why there is a sweet taste in a glucose solution.However, NaCl dissociates into Na ions and Cl ions, why does the solution still taste like NaCl? Isn't the 'taste' of salt realized when NaCl dissociates into your saliva? When salt dissolves in saliva, it becomes Na+ and Cl-. Tastebuds on our tongue contain taste receptor cells, and on those cells, there is a special sodium ion channel called ENaC (epithelial sodium channel). The dissolved sodium ions then enter into the cells through the ENaC, accumulating positive charge, creating a depolarisation in the the cell. If the depolarisation is high enough, voltage gated Ca2+ (calcium) channels will open, allowing calcium ions to diffuse in. This then stimulates NT (neurotransmitter) release through vesicle fusion(there's a whole process involving Ca2+ stimulating vesicle recruitment to the target membrane facilitated by SNAPs and SNAREs, but that stuff's complex), binding to receptors on the postsynaptic neuron and the signals are carried to the cortex where it is processed as a 'salty' taste. So you see, we don't actually detect salt as NaCl, but rather just as the Na ion itself. I'm only a second year studying physiology, so my information may not be as detailed. Well, because the whole sweet/salty/bitter/sour/(umami) thing just doesn't have a whole lot of truth to it (and the famous 'tongue map' no truth at all). "Salt" is not a single taste, it's the taste of sodium and chloride ions, together. If you were to taste some other salts, such as ammonium chloride, you can learn to tell the difference between the sodium and chlorid Continue reading >>

Aqueous Solution - Why Do Some Substances Ionize Instead Of Dissolving In Water? - Chemistry Stack Exchange

Aqueous Solution - Why Do Some Substances Ionize Instead Of Dissolving In Water? - Chemistry Stack Exchange

Why do some substances ionize instead of dissolving in water? what make something electrolyte or nonelectrolyte? I think this question stems mainly from my confusion with the definitions of ionizing and dissolving. Dissolving of a ionic substance is due to ion-dipole attraction be/wn water molecules and ionic formula unit. If water molecule has enough attraction to break down the ionic compound, the the substance will dissolve. Ionizing. Uh, all I know about it is...I don't really know. I think only ionic compound will ionize because it is composed of ions. So once it dissolves it basically ionize, right? Dissolution is simply the mixing of two phases to produce a single homogeneous phase. Ionization is a process by which a substance with no net charge is converted into one or more ions. It includes the mundane example of dissolving an ionic compound in water that dissociates into its constituent ions as well as things like forming ions by knocking electrons off with an electron beam . They're both surprisingly complex topics, but I think the question can be answered conceptually by considering a few compounds: $\ce{NaCl}$ , acetic acid ($\ce{CH3COOH}$), and glucose: All dissolve readily in water, but only two of them are electrolytes. As you note, $\ce{NaCl}$ is composed of ions and breaks apart into $\ce{Na+}$ and $\ce{Cl-}$ in solution. An electrolyte is any compound that ionizes when dissolved in a given solution, so $\ce{NaCl}$ is an electrolyte in water. Moreover, because there's is no way for a salt to be dissolved without ionizing in water (i.e. $\ce{NaCl_{(aq)}}$ isn't possible), $\ce{NaCl}$ is known as a strong electrolyte as when it dissolves, it ionizes completely. $\ce{CH3COOH}$ also dissolves readily in water, but isn't an ionic compound. Because it's a w Continue reading >>

Hydrolysis - Wikipedia

Hydrolysis - Wikipedia

Not to be confused with hydrogenolysis , hydroxylation , or water splitting . This article has multiple issues. Please help improve it or discuss these issues on the talk page . This article possibly contains original research . Please improve it by verifying the claims made and adding inline citations . Statements consisting only of original research should be removed. This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed. ( Learn how and when to remove this template message ) Generic mechanism for a hydrolysis reaction. (The 2-way yield symbol indicates an equilibrium in which hydrolysis and condensation can go both ways.) Hydrolysis ( /hadrlss/ ; from Ancient Greek hydro-, meaning 'water', and lysis, meaning 'to unbind') usually means the cleavage of chemical bonds by the addition of water . When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g. sucrose being broken down into glucose and fructose ), this is termed saccharification. Generally, hydrolysis or saccharification is a step in the degradation of a substance OR in the language of chemistry "The reaction of cation and anion or both with water molecule due to which pH is altered, cleavage of H-O bond in hydrolysis takes place." Hydrolysis can be the reverse of a condensation reaction in which two molecules join together into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water and any other solvents. Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both substance and water molecule to split into two p Continue reading >>

Types Of Aqueous Solutions

Types Of Aqueous Solutions

Unlike nonelectrolytes, electrolytes contain dissolved ions that enable them to easily conduct electricity. Recognize the properties of an electrolyte solution. Electrolytes are salts or molecules that ionize completely in solution. As a result, electrolyte solutions readily conduct electricity. Nonelectrolytes do not dissociate into ions in solution; nonelectrolyte solutions do not, therefore, conduct electricity. nonelectrolyte: A substance that does not dissociate into ions when in solution. solution: A homogeneous mixture, which may be a liquid, gas, or solid, formed by dissolving one or more substances. solute: Any substance that is dissolved in a liquid solvent to create a solution. electrolyte: A substance that dissociates into ions when in solution. salt: An ionic compound composed of cations and anions that are held together by electrostatic attraction. An electrolyte is any salt or ionizable molecule that, when dissolved in solution, will give that solution the ability to conduct electricity. This is because when a salt dissolves, its dissociated ions can move freely in solution, allowing a charge to flow. Electrolyte solutions are normally formed when a salt is placed into a solvent such as water. For example, when table salt, NaCl, is placed in water, the salt (a solid) dissolves into its component ions, according to the dissociation reaction: It is also possible for substances to react with water to yield ions in solution. For example, carbon dioxide gas, CO2, will dissolve in water to produce a solution that contains hydrogen ions, carbonate, and hydrogen carbonate ions: 2 CO2(g)+ 2 H2O(l) 3 H+(aq) + CO32-(aq) + HCO3(aq) The resulting solution will conduct electricity because it contains ions. It is important to keep in mind, however, that CO2 is not an e Continue reading >>

Ucsb Science Line

Ucsb Science Line

Hello, It is my understanding that compoundscannot be separated by physical means. Yet whenNaCl is put in water, it dissolves. As Iunderstand it, dissolving separates the compoundinto ions. Is this not a physical separation ofthe compound? I'm confused. Please help me asusual. Thank you. Excellent question! The two major types ofbonding in compounds are covalent and ionic bonds. In the covalent bond, electrons are sharedbetween two (or more) atoms, which creates a bondthat links these atoms. For instance in water,H2O, the electrons are shared betweenthe two hydrogens and the oxygen. The oxygen ismore electronegative and thus has a slightlynegative polarity. On the other hand, in theionic bond the electrons are largely isolated tothe more electronegative atom. For instance inNaCl salt, the chloride ion Cl- takes the electronfrom the metal sodium ion Na+. As a result theelectrostatic interaction between a positive andnegative ions creates this ionic bond. Generallyionic bonds are stronger than covalent bondsbecause of this electrostatic interaction, butthere is a sliding scale between covalent andionic bonds. Now, when salt is dissolved in water, somethinginteresting happens. Because water is polar (asdescribed above), it also has electrostaticinteractions with NaCl. Enough of the solventwater molecules are able to gather around the saltsuch that the combined electronegativity of wateris enough to rip the sodium from the chloride ion. Na+ is surrounded by the oxygen (negative) end ofwater, and Cl- is surrounded by the hydrogen(positive) ends of water. In this sense, water isphysically separating the salt atoms from eachother. Covalent molecules like sugar are also able todissolve in water because of slightly differentreasons. In glucose,C6H12O6, forinstance, there are mu Continue reading >>

Dissolving/dissociating

Dissolving/dissociating

SDN members see fewer ads and full resolution images. Join our non-profit community! Sugar dissolves which is a physical change. So here are my questions: 1. How does sugar dissolve if it does not dissociate into ions? 2. When something like NaCl dissociates in water, is that a physical or chemical change? 2. When something like NaCl dissociates in water, is that a physical or chemical change? I would think that NaCl would be undergoing a physical change because its chemical identity as NaCl is still the same. Chemical changes are the changes in a substance through chemical reactions . The chemical reactants form a new product with equal mass . -A physical change involves the change in a substance that does not involve a chemical reaction , as opposed to a chemical change . Since no reaction occurs, there are no chemical substances present after a physical change that were not there before the change. Because of this, a physical change is often said to be reversible. However, this definition is sometimes misleading, as many physical changes are difficult to reverse (such as cutting paper) and some chemical reactions reverse very easily (see reversible reaction ). Sugar dissolves which is a physical change. So here are my questions: 2. When something like NaCl dissociates in water, is that a physical or chemical change? Wasn't this covered in elementary school science? Wasn't this covered in elementary school science? If you have the Kaplan Blue Book check out page 277 under the solvation section. Nonionic solutes are solvated by favorable van der waals between solute-solvent. In the case of sugar, it may have something to do with all of those OH groups in sucrose. I would think that NaCl would be undergoing a physical change because its chemical identity as NaCl is sti Continue reading >>

What Is The Reaction Between Glucose And Water?

What Is The Reaction Between Glucose And Water?

What is the reaction between glucose and water? Glucose does not dissociate when dissolved in water. In comparison, a substance like sodium chloride, dissociates into sodium and chloride ions when mixed with water. And the chemical equation for that is Since glucose does not dissociate, it simply converts from solid to the aqueous form as per the following equation: `C_6H_12O_6 (s) + H_2O -> C_6H_12O_6 (aq)` In general, we are more interested in oxidation of glucose in our... Glucose does not dissociate when dissolved in water. In comparison, a substance like sodium chloride, dissociates into sodium and chloride ions when mixed with water. And the chemical equation for that is Since glucose does not dissociate, it simply converts from solid to the aqueous form as per the following equation: `C_6H_12O_6 (s) + H_2O -> C_6H_12O_6 (aq)` In general, we are more interested in oxidation of glucose in our body. When glucose reacts with oxygen, cellular respiration takes place and carbon dioxide, water and energy molecules are released. Here is the relevant equation: `C_6H_12O_6 + 6O_2 -> 6CO_2 + 6H_2O + ATP` Here ATP or adenosine triphosphate are the energy molecules. This is the reaction which produces energy in our body and that of animals. Continue reading >>

Chemistry Review | Solids | Inquiry In Action

Chemistry Review | Solids | Inquiry In Action

Some substances like salt and sugar look very similar but are actually very different. Why do solids that look similar behave differently? Some substances look the same, but behave differently. To begin to understand these differences, let's look at the physical properties of substances. Physical properties of a solid are characteristics which can be observed or measured, such as shape, size, color, and texture. Some physical properties are harder to measure, like density and hardness. Sometimes, physical properties can change. A physical change is something that alters the form or appearance of a material without changing the chemical composition. For example: When water (H2O) changes from solid ice to liquid water, that is a physical change. The chemical makeup (hydrogen and oxygen) is not altered. When salt and sugar dissolve in water it is a physical change. The chemical makeup of the salt and sugar are not changed. Why do salt and sugar dissolve differently? To understand why salt dissolves, we need to look at salt and water on the molecular level. Salt (NaCl) is made from a positive sodium ion (Na+) and a negative chloride ion (Cl-). Since positive and negative attract, the sodium ion and the chloride ion form an ionic bond, which results in NaCl. Many sodium and chloride ions attract each other and form ionic bonds to make a salt crystal. An ionic bond forms from the attraction between two oppositely charged ions. When sodium and chloride ions bond to form salt, they make a repeating, three-dimensional pattern. With salt, each sodium ion (gray sphere) is surrounded by six chloride ions (green spheres) and each chloride ion is surrounded by six sodium ions. This is why salt looks like a cube. A water molecule (H2O), is made up of two hydrogen atoms (gray) bonded Continue reading >>

What Happens When A Salt Or Sugar Dissolves In Water

What Happens When A Salt Or Sugar Dissolves In Water

WHAT HAPPENS WHEN A SALT OR SUGAR DISSOLVES IN WATER Have you ever had a relaxing salt bath? If you havent it is worth trying particularly if you have aching muscles after a vigorous game of basketball or rugby. When you throw crystals of salt into the tub water they seem to disappear in the dissolving process. No more solid salt appears to be present. Is the salt still present in the water even though you cannot see it? You can answer this question just by tasting the water. There is no doubt that the water tastes salty. As well, if you took a sample of the salty tub water in a tray and let it evaporate over the next couple of days in the sunlight salt crystals could be recovered from the solution. You may want to try this. So what do you think happened when the salt dissolved in the water? It would appear that the salt is still present in the water when it dissolves but in such small size particles that you cannot see them. We could model this dissolving process like this. A similar model would apply to the dissolving of sugar in water. The sugar particles are broken down by the water into smaller particles that you cannot see with the naked eye. Lets explore the dissolving process a little further. Apart from changing the taste of water, what other properties of water might be changed when you dissolve salt or sugar in water? Well, over a hundred years ago, scientists discovered that water will freeze at lower temperatures than zero degrees celsius when you dissolve salt or sugar in water. If you live in a climate where you get plenty of snow you will know that salt is often spread on the roads to reduce the amount of ice forming so that travelling is safer. Cars easily slide on ice so it is in the interests of road safety to lower the freezing temperature of water Continue reading >>

Why Does Water Dissolve Sugar?

Why Does Water Dissolve Sugar?

For a liquid to dissolve a solid, the molecules of the liquid and solid must attract one another. The bond between the oxygen and hydrogen atoms (OH bond) in sugar (sucrose) gives the oxygen a slight negative charge and the hydrogen a slight positive charge. Sucrose is a polar molecule. The polar water molecules attract the negative and positive areas on the polar sucrose molecules which makes sucrose dissolve in water. A nonpolar substance like mineral oil does not dissolve a polar substance like sucrose. Students will observe the dissolving of the sugar coating from an M&M when it is placed in water. Students will then help design an experiment to see if the type of liquid the M&M is placed in affects how much of the coating dissolves. Students will be able to explain, on the molecular level, how the polar characteristic of water and sugar interact so that water dissolves sugar. Students will be able to identify and control the variables in their experiment. Students will also be able to explain why a nonpolar liquid, such as mineral oil, is not good at dissolving sugar. Download the student activity sheet , and distribute one per student when specified in the activity. The activity sheet will serve as the Evaluate component of each 5-E lesson plan. Be sure you and the students wear properly fitting goggles. Isopropyl alcohol is flammable. Keep it away from flames or spark sources. Read and follow all warnings on the label. Dispose of isopropyl alcohol and mineral oil according to local regulations. Warn studens not to eat the M&Ms. Help students realize that the candy coating of an M&M is made mostly of sugar and a bit of coloring. Distribute M&Ms to students and have them look at the outside candy coating. Then have students break an M&M to look closely at the coat Continue reading >>

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