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At room temperature, fluorine is a gas of diatomic molecules, [5] pale yellow when pure (sometimes described as yellow-green). [42] It has a characteristic halogen-like pungent and biting odor detectable at 20 ppb . [ 43 ]
The noble metals ruthenium, rhodium, palladium, platinum, and gold react least readily, requiring pure fluorine gas at 300–450 °C (575–850 °F). [14] Fluorine reacts explosively with hydrogen in a manner similar to that of alkali metals. [15] The halogens react readily with fluorine gas [16] as does the heavy noble gas radon. [17]
The only chemical elements that form stable homonuclear diatomic molecules at standard temperature and pressure (STP) (or at typical laboratory conditions of 1 bar and 25 °C) are the gases hydrogen (H 2), nitrogen (N 2), oxygen (O 2), fluorine (F 2), and chlorine (Cl 2), and the liquid bromine (Br 2). [1]
The compound readily decomposes into oxygen and fluorine. Even at a temperature of −160 °C (113 K), 4% decomposes each day [1] by this process: O 2 F 2 → O 2 + F 2. The other main property of this unstable compound is its oxidizing power, although most experimental reactions have been conducted near −100 °C (173 K). [10]
The creation of sparks from metals is based on the pyrophoricity of small metal particles, and pyrophoric alloys are made for this purpose. [2] Practical applications include the sparking mechanisms in lighters and various toys, using ferrocerium; starting fires without matches, using a firesteel; the flintlock mechanism in firearms; and spark testing ferrous metals.
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 ...
Oxygen difluoride. A common preparative method involves fluorination of sodium hydroxide: . 2 F 2 + 2 NaOH → OF 2 + 2 NaF + H 2 O. OF 2 is a colorless gas at room temperature and a yellow liquid below 128 K. Oxygen difluoride has an irritating odor and is poisonous. [3]
Colors of various gases Name Formula Color Hydrogen: H 2: colorless Oxygen: O 2 pale blue Ozone: O 3 pale blue Fluorine: F 2 pale yellow Chlorine: Cl 2 greenish yellow Bromine: Br 2 red/brown Iodine: I 2 dark purple Chlorine dioxide: ClO 2 intense yellow Dichlorine monoxide: Cl 2 O brown/yellow Nitrogen dioxide: NO 2 dark brown ...