A silver block, initially at 58.2? c, is submerged into 100.0 g of water at 24.4? c, in an insulated

In order to answer this question you need to know the specific heats of silver and water.

The source below says 0.233 J/gm K and 4.186 J/gm K.

(4.186 J/g·°C) x (100.0 g) x (26.2 - 24.8) °C = 586.04 J gained by the water (and lost by the Ag)

(586.04 J) / (0.233 J/gm K) / (58.5 - 26.2) K = 77.9 g Ag