Formation of an insoluble compound will sometimes occur when a solution containing a particular cation (a positively charged ion) is mixed with another solution containing a particular anion (a negatively charged ion). The solid that separates is called a precipitate. precipitation reaction The precipitation of lead(II) iodide (plumbous iodide) results in the formation of solid yellow matter. Compounds having anions such as sulfide (S2−), hydroxide (OH−), carbonate (CO32−), and phosphate (PO43−) are often insoluble in water. A precipitate will form if a solution containing one of these anions is added to a solution containing a metal cation such as Fe2+, Cu2+, or Al3+. Fe2+(aq) + 2 OH−(aq) → Fe(OH)2(s) Al3+(aq) + PO43−(aq) → AlPO4(s) Minerals are water-insoluble compounds. Precipitation reactions in nature can account for mineral formation in many cases, such as with undersea vents called “black smokers” that form metal sulfides. liquid: Effects of chemical interactions In many cases the properties of a mixture are determined primarily by forces that are more properly classified as chemical rather than as... Two types of reactions involve transfer of a charged species. Oxidation-reduction reactions occur with electron transfer between reagents. In contrast, reactions of acids with bases in water involve proton (H+) transfer from an acid to a base. Oxidation-reduction (redox) reactions involve the transfer of one or more electrons from a reducing agent to an oxidizing agent. This has the effect of reducing the real or apparent electric charge on an atom in the substance being reduced and of increasing the real or apparent electric charge on an atom in the substance being oxidized. Simple redox reactions include the reactions of an element with oxygen. For example, magnesium burns in oxygen to form magnesium oxide (MgO). The product is an ionic compound, made up of Mg2+ and O2− ions. The reaction occurs with each magnesium atom giving up two electrons and being oxidized and each oxygen atom accepting two electrons and being reduced. Another common redox reaction is one step in the rusting of iron in damp air. 2Fe(s) + 2H2O(l) + O2(g) → 2Fe(OH)2(s) Here iron metal is oxidized to iron dihydroxide (Fe(OH)2); elemental oxygen (O2) is the oxidizing agent. Redox reactions are the source of the energy of batteries. The electric current generated by a battery arises because electrons are transferred from a reducing agent to an oxidizing agent through the external circuitry. In a common dry cell and in alkaline batteries, two electrons per zinc atom are transferred to the oxidizing agent, thereby converting zinc metal to the Zn2+ ion. In dry-cell batteries, which are often used in flashlights, the electrons given up by zinc are taken up by ammonium ions (NH4+) present in the battery as ammonium chloride (NH4Cl). In alkaline batteries, which are used in calculators and watches, the electrons are transferred to a metal oxide such as silver oxide (AgO), which is reduced to silver metal in the process. Acids and bases are important compounds in the natural world, so their chemistry is central to any discussion of chemical reactions. There are several theories of acid-base behaviour. The Arrhenius theory, named after Swedish physicist Svante August Arrhenius, views an acid as a substance that increases the concentration of the hydronium ion (H3O+) in an aqueous solution and a base as a substance that increases the hydroxide ion (OH−) concentration. Well-known acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), and acetic acid (CH3COOH). Bases includes such common substances as caustic soda (sodium hydroxide, NaOH) and slaked lime (calcium hydroxide, Ca(OH)2). Another common base is ammonia (NH3), which reacts with water to give a basic solution according to the following balanced equation. NH3(aq) + H2O(l) → NH4+(aq) + OH−(aq) (This reaction occurs to a very small extent; the hydroxide ion concentration is small but measurable.) A large number of natural bases are known, including morphine, cocaine, nicotine, and caffeine; many synthetic drugs are also bases. All of these contain a nitrogen atom bonded to three other groups, and all behave similarly to ammonia in that they can react with water to give a solution containing the hydroxide ion. Amino acids, a very important class of compounds, are able to function both as acids and as bases. Amino acid molecules contain both acidic (―COOH) and basic (―NH2) sites. In an aqueous solution, amino acids exist in both the molecular form and the so-called "zwitterionic" form, H3N + CH2CO2−. In this structure the nitrogen atom bears a positive charge, and the oxygen atom of the acid group bears a negative charge. According to the Arrhenius theory, acid-base reactions involve the combination of the hydrogen ion (H+) and the hydroxide ion to form water. An example is the reaction of aqueous solutions of sodium hydroxide and hydrochloric acid. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O (l)
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Rodrigo V. Hi, I have been trying this one but I get it wrong in the net ionic equation. Thanks for your help, appreciat it. Does a reaction occur when aqueous solutions of chromium(III) chloride and lead(II) nitrate are combined? Three blank spaces to write the net ionic equation
1 Expert Answer
A reaction does occur. both CrCl3 and Pb(NO3)2 are soluble in water so they will split up into ions. The double replacement reaction will yield (through inside/outside recombination) PbCl2 and Cr(NO3)3. All compounds with NO3- ions are soluble however, the PbCl2 compound is insoluble. Balancing the equation and eliminating all spectator ions will result in a net ionic equation of: 3Pb+2 + 6Cl- --> 3PbCl2 I hope this answered your question.