A piece of metal weighing $100 \mathrm{~g}$ is heated to $80^{\circ} \mathrm{C}$ and dropped into $1 \mathrm{~kg}$ of cold water in an insulated container at $15^{\circ} \mathrm{C}$. If the final temperature of the water in the container is $15.69^{\circ} \mathrm{C}$. If the final temperature of the water in the container is $15.69^{\circ} \mathrm{C}$, the specific heat of the metal in $\mathrm{J} / \mathrm{g} .{ }^{\circ} \mathrm{C}$ is