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For gases, departure from 3 R per mole of atoms is generally due to two factors: (1) failure of the higher quantum-energy-spaced vibration modes in gas molecules to be excited at room temperature, and (2) loss of potential energy degree of freedom for small gas molecules, simply because most of their atoms are not bonded maximally in space to ...
An enthalpy–entropy chart, also known as the H–S chart or Mollier diagram, plots the total heat against entropy, [1] describing the enthalpy of a thermodynamic system. [2] A typical chart covers a pressure range of 0.01–1000 bar , and temperatures up to 800 degrees Celsius . [ 3 ]
Since the molar heat capacity of a substance is the specific heat c times the molar mass of the substance M/N its numerical value is generally smaller than that of the specific heat. Paraffin wax , for example, has a specific heat of about 2500 J⋅K −1 ⋅kg −1 but a molar heat capacity of about 600 J⋅K −1 ⋅mol −1 .
By convention, the (higher) heat of combustion is defined to be the heat released for the complete combustion of a compound in its standard state to form stable products in their standard states: hydrogen is converted to water (in its liquid state), carbon is converted to carbon dioxide gas, and nitrogen is converted to nitrogen gas. That is ...
The specific heat capacities of iron, granite, and hydrogen gas are about 449 J⋅kg −1 ⋅K −1, 790 J⋅kg −1 ⋅K −1, and 14300 J⋅kg −1 ⋅K −1, respectively. [4] While the substance is undergoing a phase transition , such as melting or boiling, its specific heat capacity is technically undefined, because the heat goes into ...
Gas F 2: 0 Monatomic hydrogen Gas H 218 Hydrogen: Gas H 2: 0 Water: Gas H 2 O −241.818 Water: Liquid H 2 O −285.8 Hydrogen ion: Aqueous H + 0 Hydroxide ion: Aqueous OH −: −230 Hydrogen peroxide: Liquid H 2 O 2: −187.8 Phosphoric acid: Liquid H 3 PO 4: −1288 Hydrogen cyanide: Gas HCN 130.5 Hydrogen bromide: Liquid HBr −36.3 ...
The most efficient gas-fired electrical power stations can achieve 50% conversion efficiency. [citation needed] Oil- and coal-fired stations are less efficient. In a conventional automobile, the following energy transformations occur: Chemical energy in the fuel is converted into kinetic energy of expanding gas via combustion
The phase diagram shows, in pressure–temperature space, the lines of equilibrium or phase boundaries between the three phases of solid, liquid, and gas. The curves on the phase diagram show the points where the free energy (and other derived properties) becomes non-analytic: their derivatives with respect to the coordinates (temperature and ...