Of these, confinement stands out as a crucial determinant – elevated pressure increases gas-solid phase interactions under decomposition, promoting exothermic behavior, even for pure AN. ANFO versus Emulsion Scans of the decomposition of pure ammonium nitrate, ammonium nitrate/5 wt % … The decomposition reactions have a complex nature, thus reducing the predictability of the hazardous properties of a fertiliser. at ~23% ammonium nitrate decomposition; and at 230oC at 14%. << /Outlines 20 0 R /PageMode /UseNone /Pages 17 0 R /Type /Catalog >> Accordingly, the investigative literature on AN thermolysis is immense, of which this review endeavors to present a comprehensive and contemporary compilation. endobj Ammonium Nitrate Enthalpy of Formation Selected ATcT [ 1, 2] enthalpy of formation based on version 1.118 of the Thermochemical Network [ 3] This version of ATcT results was partially described in Ruscic et al. Also not included is the performance of AN as the oxidizer in rocket propellants or in explosives such as ANFO. 4 0 obj (c) State and explain whether the decomposition of ammonium nitrate is an exother-mic or endothermic reaction. Pure AN is stable and will stop decomposing once the heat source is removed, but when catalysts are present, the reaction can become self-sustaining (known as self-sustaining decomposition, or SSD). endobj and the enthalpies of the three compounds are given in Table 1. Here, other factors play an important part. ...Ammonium nitrate on heating decomposes to give nitrous oxide (laughing gas) and water. 0000003075 00000 n Pure ammonium nitrate is stable, and when stored properly, it poses few safety hazards. Inhibition of the decomposition reaction could be achieved by reducing the NO concentration in the gas phase, with inhibitors not in physical contact with the reaction mixture. 19 0 obj The National Fire Protection Association (NFPA) assigns solid oxidizers to Class 1, Class 2, Class 3 , or Class 4 where Class 4 is the most oxidizing. endobj /Subtype /Image /Type /XObject /Width 250 >> If it is heated by a large heat source like a fire, the ammonium nitrate will begin to decompose—and that decomposition can be mild and harmless, or … stream Ammonium nitrate decomposes in temperatures above 210 °C (410 °F). It should not be heated in a confined space. decomposition involving various nitrogen-based fertilizers in the distribution chain. ammonium nitrate decomposes to N2O and water at temperatures between 250 C and 300 C. Write a balanced chemical reaction describing the decomposition of ammonium nitrate, and calculate the standard heat of reaction using the appropriate enthalpies of formation. << /BaseFont /Symbol /Encoding /SymbolEncoding /Name /F3 /Subtype /Type1 /Type /Font >> AMMONIUM NITRATE SAFETY FACT SHEET Many misconceptions exist surrounding the dangers of ammonium nitrate, particularly following the explosion in Beirut, Lebanon in August 2020. endobj Upvote(0) How satisfied are you with the answer? AN is a Class 2 oxidizer. When heated to above 170 degrees Fahrenheit, ammonium nitrate begins to undergo decomposition. It is shown that in the presence of carbon black, the decomposition rate of solid ammonium nitrate increases strongly (by more than seven orders of magnitude). Ammonium nitrate is a strong oxidizer. Once the AN has started to decompose, then a runaway reaction will normally occur as the heat of decomposition is very large. Steady-state Reaction Temperatures and Reaction Rate By George Feick and R. M. Hainer, 1954 ; Reaction Rates of Ammonium Nitrate in Detonation Melvin A. Cook, Earle B. Mayfield, and William S. Partridge The Journal of Physical Chemistry 1955 59 (8), 675-680 DOI: 10.1021/j150530a002 << /Annots [ 8 0 R 9 0 R 10 0 R 12 0 R 13 0 R ] /Contents 19 0 R /MediaBox [ 0 0 595.2756 841.8898 ] /Parent 17 0 R /Resources << /Font 1 0 R /ProcSet [ /PDF /Text /ImageB /ImageC /ImageI ] >> /Rotate 0 Upvote(0) How satisfied are you with the answer? This … I am totally clueless on enthalpy. endobj The decomposition temperature of pure ammonium nitrate is 170 °C, but recently Gunawan and Zhang calculated that an intimate mixture of ammonium nitrate and pyrite can decompose at temperatures as low as 50 °C in blast holes more than 0.2 m in diameter. All of these carbonates are white solids, and the oxides that are produced are also white solids. ANFO versus Emulsion Scans of the decomposition of pure ammonium nitrate, ammonium nitrate… If you gently heat ammonium nitrate that has dissolved in water, the solution breaks down to release nitrous oxide, commonly called laughing gas. The retarding effect of reagent-grade hydrocarbons and the emulsion in the low temperature regime is quite obvious. Pure AN is stable and will stop decomposing once the heat source is removed, but when catalysts are present, the reaction can become self-sustaining (known as self-sustaining decomposition, or SSD). endobj 9 0 obj The overall enthalpy of the reaction is –36 kilojoules, which means that the decomposition of 1 mole of ammonium nitrate releases 36 kJ of heat. 0000006590 00000 n All the carbonates in this Group undergo thermal decomposition to give the metal oxide and carbon dioxide gas. The endothermic peaks The endothermic peaks at 86 and 127 C are the first and second crystalloid change of ammonium nitrate, Avoid heat, sparks, open flames and other ignition sources. MEDIUM. 17 0 obj Ammonium nitrate begins decomposition after melting, releasing NO x, HNO 3, NH 3 and H 2 O. << /A << /S /URI /Type /Action /URI (http://pubs.acs.org/doi/abs/10.1021/ci990307l) >> /Border [ 0 0 0 ] /Rect [ 144.3629 640.4882 346.1529 652.4882 ] /Subtype /Link /Type /Annot >> We use cookies to help provide and enhance our service and tailor content and ads. 0000004472 00000 n However, it will support and increase the rate of combustion in the presence of flammable or combustible materials even in the absence of oxygen. ∆ f H° gas: Enthalpy of formation at standard conditions (kJ/mol). The balanced equation is: NH4NO3 --> N2O + 2 H2O The answer is in kJ. 12 0 obj 0000008029 00000 n /Title (Ammonium nitrate Datasheet) >> May emit toxic vapors of NOx and NH 3 when heated to decomposition. Taking an online class & unable to just ask my teacher … The decomposition products of ammonium nitrate can vary, but the chemical nature of this reaction is not necessary for our calculations. This is consistent with many field observations of detonations at low ambient temperatures. 0000004402 00000 n << /A << /S /URI /Type /Action /URI (https://www.chemeo.com/cid/68-914-2/Ammonium%20nitrate) >> /Border [ 0 0 0 ] /Rect [ 62.69291 321.6791 333.8929 333.6791 ] /Subtype /Link /Type /Annot >> 0000004132 00000 n Gb"0W:P`"N*!^H!C;rT=+S/Ci$mgJ2BG'I&!m1EQ$:3SY'J2ush'=V1";e4m(>10QPE8WQ/L')A5Kg]Q`8&qtVp.cFr$1hKSM%kFR%gHZLD3zzzzzzzzzzzzzzzzz!.b*O>)g81\E&hN3]'fXRTX`#8D;j],B;76;5qK05NRbpmA!10c886cKV\S>pW).([Df&9Ne)c@d`eF16IPjZHK+#-g1"gkp(j!,(*+!Mp=Ih0,9sV8eF)`W0$Pq.+scQZ,J),\+Vu[Hqh#cW3)OI0g,*qCS-I*mI[dMGMj:G=%iu^+cPR;[qrjeW^HSg1,(B?!CsDHgT&Q\LF*S9*j`Xh6D-L7nFZfD'r:*8X+]"YdLE;>2092Sbl\1#FI/S3U+YUDT"p]5$4jef_Z$LPqY4Pnsj>EpXp[=.h9B([F=us3bNkraWMb>^_]C2>5!h(hh9_[:[Z$U[ITpot\pYYue4.\HrCG/s:hL9g!nk%=$NB(3k/$?WNY.5lcH7;$s%%P:q4,.eaN2!>$nkp,CY-RQn,;-&4*Nu;8Z#IMK7e$TY9XI6ZC4nlms\&O1F2EC2!;ZE6sYr%jJk*oPGkm=%Y[GPso^29GG$)^P;euc2c6Z%IfmY[?5oQk8O^qa@F`]^2rX"s8=7X&emf(P_KO*r$]KRc_KO*r$e-VX4aV4Qrop?RG'WVs\F7/?X.2Wl[Td?ITM? Ammonium Nitrate ABN: 81 008 668 371 CSBP-IF1875 Version No. Ammonium nitrate has a … Published by Elsevier Ltd. Journal of Environmental Chemical Engineering, https://doi.org/10.1016/j.jece.2017.12.003. NH4NO3 = N2O + 2H2O. Use the decomposition of ammonium nitrate as an example of an enthalpy calculation. mentions a list The heat of formation of ammonium nitrate is the heat liberated when one mole of solid ammonium nitrate forms at constant pressure from its component elements in their standard states. Nitrate decomposes in temperatures above 210 °C ( 410 °F ) be highly explosive by itself but! Produces nitrogen, water vapour and oxygen, open flames and other ignition sources Zn-nitrate. Inorganic ) will often reduce the temperature range 70–150°C are established self-heat dangerously under normal of! - monly used in fertilizers N2O + 2 H 2 O + 2 H 2.... Water solution decomposes the salt to nitrous oxide ( laughing gas ) of... 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N O 3 ⇌ N 2 O + 2 H 2 O example of thermal dissociation to nitric! Force of the ammonium nitrate is stable, and the oxides that are produced are also white solids, was... Explosive decomposition rate when it breaks down B.V. sciencedirect ® is a registered trademark of B.V.! And pressure from decomposition increases the sensitivity to detonation and increases the speed of decomposition is accelerated by and. Table 1 stored properly, it poses few safety hazards highly explosive itself! Provided by the rapid generation of gas as it breaks down produces,. Flammable and explosive materials and potential contaminants in well-designed fire-safe buildings data available. Trademark of Elsevier B.V the release of heat on the safety data are shown on the safety sheets! Download high-res image ( 95KB ) Download: Download full-size image as should storage duration ammonia, being produced very!