Suppose that, in the absence of a catalyst, a certain biochemical reaction occurs x times per second at normal body temperature (37 °c). in order to be physiologically useful, the reaction needs to occur 5000 times faster than when it is uncatalyzed. by how many kj/mol must an enzyme lower the activation energy of the reaction to make it useful?

Describe the forces both attractive and repulsive that occur as two atoms move closer together.

Ajar contains a certain substance. which observation would show that the substance must be either a solid or a liquid?

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?