Which term refers to large groupings of stars

The density of an unknown gas at 98°c and 740 mmhg is 2.50 g/l. what is the molar mass of the gas with work showed?

Ase your answer to this question on the information below.hydrocarbons and fissionable nuclei are among the sources used for the production of energy in the united states. a chemical reaction produces much less energy than a nuclear reaction per mole of reactant.the balanced chemical equation below represents the reaction of one molecule of a hydrocarbon with two molecules of oxygen.chemical equation: ch4 + 2o2 → co2 + 2h2o + 1.48 × 10−18 jthe nuclear equation below represents one of the many possible reactions for one fissionable nucleus. in this equation, x represents a missing product.nuclear equation: write an isotopic notation for the missing product represented by x in the nuclear equation.

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )