Determine la masa molecular del hielo de un gas si conocemos que la densidad es de 1,4 g/l

that would be in translation "the molecular mass of the ice of a gas if we know that the density is 1.4 g /l" is that all you need?

No, the correct way to answer that is -si, la quiero saber since it’s singular

Its gaviotas.  las gaviotas son aves que viven en las regiones costeras.