The rate constant for the gaseous reaction h2(g) + i2(g) → 2hi(g) is 2.42 × 10−2/(m·s) at 400°c. initially an equimolar sample of h2 and i2 is placed in a vessel at 400°c and the total pressure is 1670 mmhg. (a) what is the initial rate (m·min) of formation of hi? (b) what are the rate of formation of hi and the concentration of hi (in molarity) after 14.5 min? rate of formation = (m/min) [hi] = m

The allotropes of carbon include a variety of structures that include three-dimensional tetrahedral lattices, planes of hexagonal rings, cylindrical tubes of hexagonal rings, and spheres of five- and six-membered rings. similar shapes of network covalent atomic solids are possible with carbon nitride, boron, and pure silicon (e.g., silicene is a graphene-like allotrope of pure silicon). in contrast, silicates exist as either highly ordered or amorphous (more random) three-dimensional lattices. what could explain why there are there no naturally occurring sheets, stacked sheets, cylindrical tubes, or spheres of network covalent atomic solids composed of silicon and oxygen (sio2)? would pure silicate structures make good lubricants or good electrical conductors?