It’s possible to boil water by adding hot rocks to it, a technique that has been used in many societies over time. If you heat a rock in the fire, you can easily get it to a temperature of 500°C. If you use granite or other similar stones, the specific heat is about 800 J/kg # K. If 5.0 kg of water at 10°C is in a leak-proof vessel, what minimum number of 1.0 kg stones must be added to bring the water to a boil?