Search results
Results from the WOW.Com Content Network
For example, R-22 has one carbon atom, one hydrogen atom (2−1 = 1), two fluorine atoms, and one chlorine atom (4−2−1 = 1), so it is chlorodifluoromethane, while R-134 has two carbon atoms (2−1 = 1), two hydrogen atoms (3−1 = 2), four fluorine atoms, and no chlorine atoms (6−2−4 = 0), so it is one of the tetrafluoroethanes. This ...
2,2-Dichloro-1,1,1-trifluoroethane can be produced by reacting tetrachloroethylene with hydrogen fluoride in the gas phase. This is an exothermic reaction and requires a catalyst: This is an exothermic reaction and requires a catalyst:
For example, consider Halon 1211. This halon has number 1211 in its name, which tells it has 1 carbon atom, 2 fluorine atoms, 1 chlorine atom, and 1 bromine atom. A single carbon only has four bonds, all of which are taken by the halogen atoms, so there is no hydrogen. Thus its formula is CF 2 ClBr, hence its IUPAC name is ...
Aztec women are handed flowers and smoking tubes before eating at a banquet, Florentine Codex, 16th century. Smoking's history dates back to as early as 5000–3000 BC, when the agricultural product began to be cultivated in Mesoamerica and South America; consumption later evolved into burning the plant substance either by accident or with intent of exploring other means of consumption. [1]
The power pack can be changed in the field in 35 minutes. [60] The engine and transmission are separated from the crew compartment through a fireproof bulkhead. [81] An enhanced version of the EuroPowerPack, with a 1,650 PS (1.2 MW) MTU MT883 engine has been trialled by the Leopard 2. [81]
In May 2014, USNI News reported that 21 of the 28 Flight I and II Arleigh Burke-class destroyers would not receive the full mid-life upgrade that included electronics and Aegis Baseline 9 software for SM-6 compatibility; instead, they would retain the basic BMD 3.6.1 software in a $170 million upgrade concentrating on HM&E systems, and on some ...
[6] [7] In June 1974, Marsh supermarket in Troy, Ohio used a scanner made by Photographic Sciences Corporation to scan the Universal Product Code (UPC) barcode on a pack of Wrigley's chewing gum. [ 8 ] [ 5 ] QR codes , a specific type of 2D barcode, rose in popularity in the second decade of the 2000s due to the growth in smartphone ownership.