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Methane's heat of combustion is 55.5 MJ/kg. [25] Combustion of methane is a multiple step reaction summarized as follows: CH 4 + 2 O 2 → CO 2 + 2 H 2 O (ΔH = −891 kJ/mol, at standard conditions) Peters four-step chemistry is a systematically reduced four-step chemistry that explains the burning of methane.
Table data obtained from CRC Handbook of Chemistry and Physics 44th ed. Annotation "(s)" indicates equilibrium temperature of vapor over solid. Otherwise temperature is equilibrium of vapor over liquid.
The kilogram per cubic metre (symbol: kg·m −3, or kg/m 3) is the unit of density in the International System of Units (SI). It is defined by dividing the SI unit of mass, the kilogram, by the SI unit of volume, the cubic metre. [1]
— "Values ranging from 21.3 to 21.5 gm/cm 3 at 20 °C have been reported for the density of annealed platinum; the best value being about 21.45 gm/cm 3 at 20 °C." 21.46 g/cm 3 — Rose, T. Kirke. The Precious Metals, Comprising Gold, Silver and Platinum .
Therefore, the amount of mass that can be lifted by hydrogen in air at sea level, equal to the density difference between hydrogen and air, is: (1.292 - 0.090) kg/m 3 = 1.202 kg/m 3. and the buoyant force for one m 3 of hydrogen in air at sea level is: 1 m 3 × 1.202 kg/m 3 × 9.8 N/kg= 11.8 N
The standard unit is the meter cubed per kilogram (m 3 /kg or m 3 ·kg −1). Sometimes specific volume is expressed in terms of the number of cubic centimeters occupied by one gram of a substance. In this case, the unit is the centimeter cubed per gram (cm 3 /g or cm 3 ·g −1 ).
The Cassini data indicated the rivers carry pure liquid methane that then mixes into the more ethane-rich liquids of the seas, much as freshwater in Earth's rivers mixes into saltwater oceans.
In terms of density, m = ρV, where ρ is the volumetric mass density, V is the volume occupied by the mass. This energy can be released by the processes of nuclear fission (~ 0.1%), nuclear fusion (~ 1%), or the annihilation of some or all of the matter in the volume V by matter– antimatter collisions (100%).