Ammonium nitrate decomposes explosively upon heating according to the balanced equation: 2nh4no3(s)→2n2(g) o2(g) 4h2o(g) part a calculate the total volume of gas (at 24 âc and 749 mmhg ) produced by the complete decomposition of 1.56 kg of ammonium nitrate.

 the total volume  of   gas is 1687.75 L

Calculation

2NH4NO3→ 2N2(g) +O2(g) + 4 H2O(g)

Volume of a gas is calculated using ideal gas equation

that is Pv=nRT

P(pressure)= 749 mm Hg

V(volume)=?

n (no of moles)

to  calculate the  number  of  moles  of  gas.

  find  the  moles of NH4NO3

  moles=mass/molar  mass

  mass=1.56 kg = 1.56 x 1000 = 1560 g

 molar mass of NH4NO3 =14+(1 x4) + 14 +( 16  x3) = 80 g/mol

moles= 1560 g/80 g/mol=19.5 moles

by use of mole ratio of NH4NO3 : total number of  mole of a gas  from equation above  which is = 2:7 therefore the moles of gas = 19.5 x7/2 =68.25 moles

therefore n=68.35 mole

R( gas  constant)  =62.36367  L.mmhg/mol.K

T(temperature) =24°c into k = 24 +273=297K

by  making V the subject of the formula

v=nRT/P

V= (68.25  mol  x 62.36367 L.mmhg/mol.k  x 297 k) / 749  mmhg = 1687.75 L

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.