Molecular equation aqueous ionic reactions

Chemists use three types of equations to represent aqueous ionic reactions molecular, total ionic, and net ionic equations. As you ll see in the two types of ionic equations, by balancing the atoms, we also balance the charges. 

Figure 4.4 An aqueous ionic reaction and its equations. When silver nitrate and sodium chromate solutions are mixed, a reaction occurs that forms solid silver chromate and a solution of sodium nitrate. The photos present the macroscopic view of the reaction, the view the chemist sees in the lab. The blow-up arrows lead to an atomic-scale view, a representation of the chemist s mental picture of the reactants and products. (The pale ions are spectator ions, present for electrical neutrality, but not involved in the reaction.) Three equations represent the reaction in symbols. (The ions that are reacting are shown in red type.) The molecular equation shows all substances intact. The total Ionic equation shows all soluble substances as separate, solvated ions. The net Ionic equation eliminates the spectator ions to show only the reacting species.

A molecular equation for an aqueous ionic reaction shows undissociated substances. A total Ionic equation shows all soluble Ionic compounds as separate, solvated ions. Spectator ions appear unchanged on both sides of the equation. By eliminating them, you see the actual chemical change in a net ionic equation. 

Although this equation shows the reactants and products of the reaction, it does not give a very clear picture of what actually occurs in solution. As we have seen, aqueous solutions of potassium chromate, barium nitrate, and potassium nitrate contain the individual ions, not molecules, as is implied by the molecular equation. Thus the complete ionic equation... 

For the following aqueous reactions, complete and balance the molecular equation and write a net ionic equation ... 

For the reaction between aqueous solutions of acetic acid (CH3COOH) and barium hydroxide, Ba(OH)2, write (a) the balanced molecular equation, (b) the complete ionic equation, (c) the net ionic equation. 

Frequently, the compounds involved in aqueous chemistry are ionic, as is true for both HNO3 and NH4NO3 in this example. These ionic compounds dissociate when they dissolve in water, so the actual solution does not contain intact molecules of these compounds. This dissociation is emphasized if we write the total ionic equation rather than the molecular equation. This form emphasizes what is actually present in the reacting mixture by writing dissociated compounds as separated ions in the solution. The total ionic equation for our example reaction from above is thus... 

One requirement for a reaction to occur is that the chemicals involved must be able to mix and interact with one another. Thus the physical state of the reactants can be important. In particular, an aqueous solution is often used as the medium for a reaction. To describe reactions in the aqueous phase effectively, we often need to specify the molar concentration of the solutions used. We also have options about how to write the chemical reaction itself—as a molecular equation, for example, or a net ionic equation. Several classes of chemical reactions, such as precipitation reactions or acid-base neutralizations, are sufficiently common that additional definitions have been established to improve our ability to communicate about them. 

Write a balanced molecular equation and a net ionic equation for the reaction that occurs when (a) solid CaCOg reacts with an aqueous solution of nitric add (b) solid iron(II) sulfide reacts with an aqueous solution of hydro-bromic acid. 

Three types of equations describe an aqueous reaction. A molecular equation shows all substances as intact compounds. A total ionic equation shows ions for all soluble substances. A net ionic equation is more useful because it omits spectator ions (those not involved in the reaction) and shows the actual chemical change taking place. Section 4.2)... 

The molecular and total ionic equations above show that if you evaporate the water, the spectator ions remain the ionic compound that results from the reaction of an acid and a base is called a salt, which in this case is barium chloride. Thus, in an aqueous neutralization reaction, an acid and a base form a salt solution and water ... 

In the previous section, we used a precipitation reaction to illustrate how to convert a molecular equation to an ionic equation. A precipitation reaction occurs in aqueous solution because one product is insoluble. A precipitate is an insoluble solid compound formed during a chemical reaction in solution. To predict whethCT a precipitate will form when you mix two solutions of ionic compounds, you need to know whether any of the potential products that might form are insoluble or not This is another application of the solubility rules (Section 4.1). 

You mix aqueous solutions of sodium iodide and lead(II) acetate. If a reaction occurs, write the balanced molecular equation and the net ionic equation. If no reaction occurs, indicate this by writing the formulas of the compounds and an arrow followed by NR. 

Potassium carbonate solution reacts with aqueous hy-drobromic acid to give a solution of potassium bromide, carbon dioxide gas, and water. Write the molecular equation and the net ionic equation for the reaction. 

The following reactions occur in aqueous solution. Complete and balance the molecular equations using phase labels. Then write the net ionic equations. 

Lead(II) nitrate reacts with cesium sulfate in an aqueous precipitation reaction. What are the formulas of lead(II) nitrate and cesium sulfate Write the molecular equation and net ionic equation for the reaction. What are the names of the products Give the molecular equation for another reaction that produces the same precipitate. 

Barium carbonate is the source of barium compounds. It is produced in an aqueous precipitation reaction from barium sulfide and sodium carbonate. (Barium sulfide is a soluble compound obtained by heating the mineral barite, which is barium sulfate, with carbon.) What are the molecular equation and net ionic equation for the precipitation reaction A solution containing 33.9 g of barium sulfide requires 21.2 g of sodium carbonate to react completely with it, and 15.6 g of sodium sulfide is produced in addition to whatever barium carbonate is obtained. How many grams of barium sulfide are required to produce 10.0 tons of barium carbonate (One ton equals 2000 pounds.)... 

Although molecular equations are useful, especially from the standpoint of knowing which solutions to combine in the laboratory, they are in a sense unrealistic. Soluble ionic compounds are strong electrolytes [W Section 4.1]. As such, they exist in solution as hydrated ions, rather than as formula units Thus, it would be more realistic to represent the aqueous species in the reaction of Na2S04(a ) with Ba(OH)2(n ) as follows ... 

Throughout the remainder of this book we will usually write net ionic equations for reactions that take place in aqueous solution. For reactions occurring in the gas phase, or between liquids other than water, we will continue to write total molecular equations. 

Representing Aqueous Reactions Molecular, Ionic, and Complete Ionic Equations 166... 

Finally, balance the equation. FOR PRACTICE 4.15 Write a molecular equation for the gas-evolution reac when you mix aqueous hydrobromic acid and aqueou FOR MORE PRACTICE 4.15 Write a net ionic equation for the reaction that occurs hydroiodic acid with calcium sulfide. 2HN03(fl ) Na2CO3(flg) H2O(0 + C02(g) + 2NaN03(a ) tion that occurs s potassium sulfite. when you mix... 

Electronic structure methods are aimed at solving the Schrodinger equation for a single or a few molecules, infinitely removed from all other molecules. Physically this corresponds to the situation occurring in the gas phase under low pressure (vacuum). Experimentally, however, the majority of chemical reactions are carried out in solution. Biologically relevant processes also occur in solution, aqueous systems with rather specific pH and ionic conditions. Most reactions are both qualitatively and quantitatively different under gas and solution phase conditions, especially those involving ions or polar species. Molecular properties are also sensitive to the environment. 

A wide variety of new approaches to the problem of product separation in homogeneous catalysis has been discussed in the preceding chapters. Few of the new approaches has so far been commercialised, with the exceptions of a the use of aqueous biphasic systems for propene hydroformylation (Chapter 5) and the use of a phosphonium based ionic liquid for the Lewis acid catalysed isomerisation of butadiene monoxide to dihydrofuran (see Equation 9.1). This process has been operated by Eastman for the last 8 years without any loss or replenishment of ionic liquid [1], It has the advantage that the product is sufficiently volatile to be distilled from the reactor at the reaction temperature so the process can be run continuously with built in product catalyst separation. Production of lower volatility products by such a process would be more problematic. A side reaction leads to the conversion of butadiene oxide to high molecular weight oligomers. The ionic liquid has been designed to facilitate their separation from the catalyst (see Section 9.7)... 

Use the Ionic Compounds activity (eChapter 4.4) to determine the formula of each of the insoluble iron(III) salts. Then, using your knowledge of the solubility rules, write a molecular, ionic, and net ionic equation for an aqueous reaction that would produce each salt. 

Reactions of cations in aqueous solution with sodium hydroxide - Al3+, Fe2+, Fe3+, Cu2+, Ca2+, Zn2, Cr3+,. An excess of sodium hydroxide solution is added slowly to a small volume of the solution containing the cation. This is an exercise in observation, organisational and recording skills and in the ability to write chemical equations - word, molecular and ionic. 

Since covalent compounds do not produce ions in aqueous solution, write their molecular formulas. Water is a common example, because it dissociates only very slightly into ions. When a reaction involves a gas, always include the gas in the net ionic equation. 

Write the balanced molecular, complete, and net ionic equations for the reaction, if any, that occurs when aqueous solutions of the following are mixed. 

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