If the half-life of Uranium-235 is 176000 years and 12.5 g of Uranium-235 remain after 704000 years, how much of the radioactive isotope was in the original sample.

What type of reaction is represented by the following example? 2co2 (g) + 4h2o (l) + 1452 kj 2ch3oh (l) (g) + 3o2 (g) exothermic endothermic

Silica, sio2, is formed on silicon as an electrically insulating layer for microelectronic devices. silica is formed when silicon is exposed to o2 gas at an elevated temperature. at 900˚c, it takes 90 minutes for the oxygen to diffuse from the surface to form a 0.06 micron (0.06 x 10-6 m) thick layer of sio2 on

Which type of bonding involves the complete transfer of a valence electron from a less electrogrative atom to a more electronegative one