Reversible reactions

Time remains (roughly) constant.The formation of NO2 from N2O4 is a reversible reaction, which is identified by the equilibrium arrow [latex]\rightleftharpoons[/latex] . All reactions are reversible, but many reactions, for all practical purposes, proceed in one direction until the reactants are exhausted and will reverse only under certain conditions. Such reactions are often depicted with a one-way arrow from reactants to products. Many other reactions, such as the formation of NO2 from N2O4, are reversible under more easily obtainable conditions and, therefore, are named as such. In a reversible reaction, the reactants can combine to form products and the products can react to form the reactants. Thus, not only can N2O4 decompose to form NO2, but the NO2 produced can react to form N2O4. As soon as the forward reaction produces any NO2, the reverse reaction begins and NO2 starts to react to form N2O4. At equilibrium, the concentrations of N2O4 and NO2 no longer change because the rate of formation of NO2 is exactly equal to the rate of consumption of NO2, and the rate of formation of N2O4 is exactly equal to the rate of consumption of N2O4.Chemical equilibrium is a dynamic process: As with the swimmers and the sunbathers, the numbers of each remain constant, yet there is a flux back and forth between them Figure 2.In a chemical equilibrium, the forward and reverse reactions do not stop, rather they continue to occur at the same rate, leading to constant concentrations of the reactants and the products. Plots showing how the reaction rates and concentrations change with respect to time are shown in Figure 1.We can detect a state of equilibrium because the concentrations of reactants and products do not appear to change. However, it is important that we verify that the absence of change is due

HomeessaY outlinepolitical science notesCHEMISTRY NOTESPHYSICS NOTES HomeCHEMISTRY NOTESReversible and Irreversible Reactions: Understanding the Basics Reversible and Irreversible Reactions: Understanding the Basics Reversible Reaction :A reversible reaction is a chemical reaction that can proceed in both forward and backward directions, resulting in the formation of an equilibrium mixture of reactants and products.Example :N2 (g) + 3H2 (g) ⇌ 2NH3 (g)In this reaction, nitrogen gas (N2) reacts with hydrogen gas (H2) to form ammonia (NH3). However, the reaction can also proceed in the reverse direction, where ammonia decomposes back into nitrogen and hydrogen gases.Forward Reaction :N2 (g) + 3H2 (g) → 2NH3 (g)Reverse Reaction :2NH3 (g) → N2 (g) + 3H2 (g)Equilibrium :The forward and reverse reactions occur simultaneously, and the concentrations of the reactants and products reach a state of equilibrium.Diagram: N2 (g) + 3H2 (g) ⇌ 2NH3 (g) Forward Reaction Reverse Reaction N2 + 3H2 → 2NH3 2NH3 → N2 + 3H2 Equilibrium: Equilibrium: N2 + 3H2 ⇌ 2NH3 2NH3 ⇌ N2 + 3H2Irreversible Reaction :An irreversible reaction is a chemical reaction that proceeds in only one direction, resulting in the complete conversion of reactants to products. In other words, the reaction cannot be reversed, and the products cannot be converted back into the reactants.Example: 2Na(s) + 2H2O → 2NaOHThe reaction between sodium (Na) and water (H2O) to form sodium hydroxide (NaOH) is an example of an irreversible reaction.Reaction Equation :2Na(s) + 2H2O → 2NaOHDescription :In this reaction, sodium (Na) reacts with water (H2O) to form sodium hydroxide (NaOH). The reaction is highly exothermic, releasing a large amount of heat energy. The reaction is also highly irreversible, meaning that the products (NaOH) cannot be converted back into the reactants (Na and H2O).Why is this reaction irreversible?There are several reasons why this reaction is irreversible:1. Highly exothermic : The reaction releases a large amount of heat energy, making it highly exothermic. This means that the reaction is highly favorable, and the products are highly stable.2. Formation of a strong base : Sodium hydroxide (NaOH) is a strong base, which means that it is highly reactive and cannot be easily converted back into its constituent elements.3. No reverse reaction : There is no known reverse reaction that can convert sodium hydroxide (NaOH) back into sodium (Na) and water (H2O).In summary, reversible reactions can proceed in both forward and backward directions, resulting in an equilibrium mixture of reactants and products. Irreversible reactions, on

Be established. If the bottle were not capped, the bromine vapor would escape and no equilibrium would be reached.Key Concepts and SummaryA reaction is at equilibrium when the amounts of reactants or products no longer change. Chemical equilibrium is a dynamic process, meaning the rate of formation of products by the forward reaction is equal to the rate at which the products re-form reactants by the reverse reaction.ExercisesWhat does it mean to describe a reaction as “reversible”?When writing an equation, how is a reversible reaction distinguished from a nonreversible reaction?If a reaction is reversible, when can it be said to have reached equilibrium?Is a system at equilibrium if the rate constants of the forward and reverse reactions are equal?If the concentrations of products and reactants are equal, is the system at equilibrium?Glossaryequilibrium: in chemical reactions, the state in which the conversion of reactants into products and the conversion of products back into reactants occur simultaneously at the same rate; state of balancereversible reaction: chemical reaction that can proceed in both the forward and reverse directions under given conditions Candela Citations CC licensed content, Shared previouslyChemistry. Provided by: OpenStax College. Located at: License: CC BY: Attribution. License Terms: Download for free at

Azulfidine (sulfasalazine) side effects list for healthcare professionalsThe most common adverse reactions associated withsulfasalazine are anorexia, headache, nausea, vomiting, gastric distress, andapparently reversible oligospermia. These occur in about one-third of thepatients. Less frequent adverse reactions are skin rash, pruritus, urticaria,fever, Heinz body anemia, hemolytic anemia, and cyanosis, which may occur at afrequency of one in every thirty patients or less. Experience suggests thatwith a daily dosage of 4 g or more, or total serum sulfapyridine levels above50 μg/mL, the incidence of adverse reactions tends to increase.Although the listing which follows includes a few adversereactions which have not been reported with this specific drug, thepharmacological similarities among the sulfonamides require that each of thesereactions be considered when Azulfidine Tablets are administered. Less commonor rare adverse reactions include:Blood dyscrasias: aplastic anemia,agranulocytosis, leukopenia, megaloblastic (macrocytic) anemia, purpura, thrombocytopenia,hypoprothrombinemia, methemoglobinemia, congenital neutropenia, andmyelodysplastic syndrome.Hypersensitivity reactions: erythema multiforme(Stevens-Johnson syndrome), exfoliative dermatitis, epidermal necrolysis(Lyell's syndrome) with corneal damage, drug rash with eosinophilia andsystemic symptoms (DRESS), anaphylaxis, serum sickness syndrome, interstitiallung disease, pneumonitis with or without eosinophilia, vasculitis, fibrosingalveolitis, pleuritis, pericarditis with or without tamponade, allergic myocarditis,polyarteritis nodosa, lupus erythematosus-like syndrome, hepatitis and hepaticnecrosis with or without immune complexes, fulminant hepatitis, sometimesleading to liver transplantation, parapsoriasis varioliformis acuta(Mucha-Haberman syndrome), rhabdomyolysis, photosensitization, arthralgia,periorbital edema, conjunctival and scleral injection, and alopecia.Gastrointestinal reactions: hepatitis, hepaticfailure, pancreatitis, bloody diarrhea, impaired folic acid absorption,impaired digoxin absorption, stomatitis, diarrhea, abdominal pains, andneutropenic enterocolitis.Central nervous system reactions: transversemyelitis, convulsions, meningitis, transient lesions of the posterior spinalcolumn, cauda equina syndrome, Guillian-Barre syndrome, peripheral neuropathy,mental depression, vertigo, hearing loss, insomnia, ataxia, hallucinations,tinnitus, and drowsiness.Renal reactions: toxic nephrosis with oliguria andanuria, nephritis, nephrotic syndrome, urinary tract infections, hematuria,crystalluria, proteinuria, and hemolytic-uremic syndrome.Other reactions: urine discoloration and skindiscoloration.The sulfonamides bear certain chemical similarities tosome goitrogens, diuretics (acetazolamide and the thiazides), and oralhypoglycemic agents. Goiter production, diuresis and hypoglycemia have occurredrarely in patients receiving sulfonamides. Cross-sensitivity may exist withthese agents. Rats appear to be especially susceptible to the goitrogenic effectsof sulfonamides and long-term administration has produced thyroid malignanciesin this species.Postmarketing ReportsThe following events have been identified duringpost-approval use of products which contain (or are metabolized to) mesalaminein clinical practice.

ADVERSE REACTIONSThe most common adverse reactions associated with sulfasalazine are anorexia, headache, nausea, vomiting, gastric distress, and apparently reversible oligospermia. These occur in about one-third of the patients. Less frequent adverse reactions are skin rash, pruritus, urticaria, fever, Heinz body anemia, hemolytic anemia, and cyanosis, which may occur at a frequency of one in every thirty patients or less. Experience suggests that with a daily dosage of 4 g or more, or total serum sulfapyridine levels above 50 µg/mL, the incidence of adverse reactions tends to increase.Although the listing which follows includes a few adverse reactions which have not been reported with this specific drug, the pharmacological similarities among the sulfonamides require that each of these reactions be considered when AZULFIDINE Tablets are administered. Less common or rare adverse reactions include:Blood dyscrasias: aplastic anemia, agranulocytosis, leukopenia, megaloblastic (macrocytic) anemia, purpura, thrombocytopenia, hypoprothrombinemia, methemoglobinemia, congenital neutropenia, and myelodysplastic syndrome.Hypersensitivity reactions: erythema multiforme, epidermal necrolysis (SJS/TEN) with corneal damage, exfoliative dermatitis, DRESS, anaphylaxis, serum sickness syndrome, interstitial lung disease, pneumonitis with or without eosinophilia, vasculitis, fibrosing alveolitis, pleurisy/pleuritis, pericarditis with or without tamponade, allergic myocarditis, polyarteritis nodosa, lupus erythematosus-like syndrome, hepatitis and hepatic necrosis with or without immune complexes, fulminant hepatitis, sometimes leading to liver transplantation, parapsoriasis varioliformis acuta (Mucha-Haberman syndrome), rhabdomyolysis, photosensitization, arthralgia, periorbital edema, conjunctival and scleral injection, and alopecia.Gastrointestinal reactions: hepatitis, hepatic failure, pancreatitis, bloody diarrhea, impaired folic acid absorption, impaired digoxin absorption, stomatitis, diarrhea, abdominal pains, and neutropenic enterocolitis.Central nervous system reactions: transverse myelitis, convulsions, meningitis, transient lesions of the posterior spinal column, cauda equina syndrome, Guillian-Barre syndrome, peripheral neuropathy, mental depression, vertigo, hearing loss, insomnia, ataxia, hallucinations, tinnitus, and drowsiness.Renal reactions: toxic nephrosis with oliguria and anuria, nephritis, nephrotic syndrome, urinary tract infections, hematuria, crystalluria, proteinuria, and hemolytic-uremic syndrome.Other reactions: urine discoloration and skin discoloration.The sulfonamides bear certain chemical similarities to some goitrogens, diuretics (acetazolamide and the thiazides), and oral hypoglycemic agents. Goiter production, diuresis and hypoglycemia have occurred rarely in patients receiving sulfonamides. Cross-sensitivity may exist with these agents. Rats appear to be especially susceptible to the goitrogenic effects of sulfonamides and long-term administration has produced thyroid malignancies in this species.Postmarketing ReportsThe following events have been identified during post-approval use of products which contain (or are metabolized to) mesalamine in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of seriousness, frequency of reporting, or potential causal connection to mesalamine:Blood dyscrasias: pseudomononucleosisCardiac disorders: myocarditisHepatobiliary disorders: reports of hepatotoxicity, including elevated liver function tests (SGOT/AST, SGPT/ALT, GGT, LDH, alkaline phosphatase, bilirubin), jaundice, cholestatic jaundice, cirrhosis, hepatitis cholestatic, cholestasis and possible hepatocellular damage including liver necrosis and