Check all statements below that are true.
heating air under the balloon will cause the
air inside to expand.
the air inside will have the same mass but
more volume.
heating the air under the balloon will cause
the entire balloon to rise.
the outside temperature will have no affect
on the height of the balloon.
the only way to make the balloon sink is to
let out the air

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?