Answer to Question #267077 in Physics for Jude

Question

How much heat is needed to change the temperature of a 2.0 kg of block of copper from

10°C to 140°C? (5 points)

2. How much steam at 1000C must be added to 163g of water at 25°C contained in a 30 g

glass vessel to produce water at 770C? (10 points)

3. The density of gold at 20°C is 19,300kg/m3. Find the density at 100°C. (10 points)

Answer 1

1) The heat required (specific heat of copper is 385 J/(kg·K):

$$Q=cm\Delta t=100100\text{ J}.$$

2) Thermal equilibrium:

$$c_sm_s(770-1000)+c_wm_w(100-25)+r_wm_w+\\+c_sm_w(770-100)+c_gm_g(770-25)=0,\\\space\\ m_s=1.4\text{ kg}.$$

Heat of vaporization: 2257 kJ/kg, specific heat of glass: 670 J/(kg·K), of water: 4200 J/(kg·K), of steam: 2100 J/(kg·K).