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In aqueous solution, ammonia deprotonates a small fraction of the water to give ammonium and hydroxide according to the following equilibrium: . NH 3 + H 2 O ⇌ NH + 4 + OH −.. In a 1 M ammonia solution, about 0.42% of the ammonia is converted to ammonium, equivalent to pH = 11.63 because [NH +
A mixture of ammonia gas and water vapor is introduced into a reactor that contains a saturated solution of ammonium sulfate and about 2% to 4% of free sulfuric acid at 60 °C. Concentrated sulfuric acid is added to keep the solution acidic, and to retain its level of free acid. The heat of reaction keeps reactor temperature at 60 °C.
[88] [89] The raw energy density of liquid ammonia is 11.5 MJ/L, [88] which is about a third that of diesel. Ammonia can be converted back to hydrogen to be used to power hydrogen fuel cells, or it may be used directly within high-temperature solid oxide direct ammonia fuel cells to provide efficient power sources that do not emit greenhouse gases.
Liquid nitrogen is a compact and readily transported source of dry nitrogen gas, as it does not require pressurization. Further, its ability to maintain temperatures far below the freezing point of water, specific heat of 1040 J ⋅kg −1 ⋅K −1 and heat of vaporization of 200 kJ⋅kg −1 makes it extremely useful in a wide range of ...
The relationship between the two constants is R s = R / m, where m is the molecular mass of the gas. The US Standard Atmosphere (USSA) uses 8.31432 m 3 ·Pa/(mol·K) as the value of R . However, the USSA in 1976 does recognize that this value is not consistent with the values of the Avogadro constant and the Boltzmann constant .
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.
The following table lists the Van der Waals constants (from the Van der Waals equation) for a number of common gases and volatile liquids. [ 1 ] To convert from L 2 b a r / m o l 2 {\displaystyle \mathrm {L^{2}bar/mol^{2}} } to L 2 k P a / m o l 2 {\displaystyle \mathrm {L^{2}kPa/mol^{2}} } , multiply by 100.
Solid monoammonium phosphate can be considered stable in practice for temperatures up to 200 °C, when it decomposes into gaseous ammonia NH 3 and molten phosphoric acid H 3 PO 4. [9] At 125 °C the partial pressure of ammonia is 0.05 mm Hg. [10] A solution of stoichometric monoammonium phosphate is acidic (pH 4.7 at 0.1% concentration, 4.2 at ...