Directions: each set of lettered choices below refers to the numbered words or statements immediately following it. select the one lettered choice that best fits each word or statement. a choice may be used once, more than once, or not at all in each set. the figure below represents a food web in a particular ecosystem. each letter represents a species. the arrows indicate the direction of energy flow.
the gases are contained in a reaction vessel and are in equilibrium at 298 k
(a) activation energy
(b) total mass of the system
(c) molar concentration of xz4g)
(d) number of molecules present (e) equilibrium constant
1. is decreased by the addition of a catalyst
2. is decreased when the volume of the reaction vessel is increased and equilibrium is reestablished at 298 k

Nanotechnology, the field of trying to build ultrasmall structures one atom at a time, has progressed in recent years. one potential application of nanotechnology is the construction of artificial cells. the simplest cells would probably mimic red blood cells, the body's oxygen transporters. for example, nanocontainers, perhaps constructed of carbon, could be pumped full of oxygen and injected into a person's bloodstream. if the person needed additional oxygen-due to a heart attack perhaps, or for the purpose of space travel-these containers could slowly release oxygen into the blood, allowing tissues that would otherwise die to remain alive. suppose that the nanocontainers were cubic and had an edge length of 24 nanometers. part a part complete what is the volume of one nanocontainer? (ignore the thickness of the nanocontainer's wall.) express your answer using two significant figures. v v = 1.4ă—10â’20 l previous answers correct significant figures feedback: your answer 1.3824â‹…10â’20 = 1.382ă—10â’20 l was either rounded differently or used a different number of significant figures than required for this part. if you need this result for any later calculation in this item, keep all the digits and round as the final step before submitting your answer. part b suppose that each nanocontainer could contain pure oxygen pressurized to a density of 81 g/l . how many grams of oxygen could be contained by each nanocontainer?