If a reaction is reversible, what are the relative amounts of reactant and product at the end of the reaction? no reactant; all product
no product, all reactant
some product; some reactant

Ok so co(g) is not pronoused that. the only clue is that youpronouse it the oppisote way. 

We first assume that this gas is an ideal gas where it follows the ideal gas equation. the said equation is expressed as: pv = nrt. from this equation, we can predict the changes in the pressure, volume and temperature. if the volume and the temperature of this gas is doubled, then the pressure still stays the same.

Answersublimation;

D=m/v =57.9/3 = 19.3 g/cm^3