Humans exhale carbon dioxide when they breathe. if the concentration of carbon dioxide in the air that people breathe gets too high, it can be fatal. therefore, in space shuttles, submarines, and other sealed environments, it is common to use "air scrubbers" to remove carbon dioxide from the air. the air scrubbers on the space shuttle remove carbon dioxide by using lithium hydroxide (lioh). the reaction in the air scrubbers is shown below: co2 2lioh li2co3 h2o each astronaut produces 8.8 × 102 g co2 per day that must be removed from the air on the shuttle. if a typical shuttle mission is 9 days, and the shuttle can carry 3.50 × 104 g lioh, what is the maximum number of people the shuttle can safely carry for one mission?

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?