A $1\mathrm{.}48$ g sample of a compound containing only carbon, hydrogen, nitrogen and chlorine was burned in excess O$2$ to yield $2\mathrm{.}21$ g of CO$2$ and $0\mathrm{.}452$ g of H$2$O$.$ Another sample of this compound, of mass $2\mathrm{.}62$ g$,$ was found to contain $1\mathrm{.}05$ g of chlorine. Calculate the empirical formula of the compound.