You have a 2.00 kg block of lead. Lead melts at 327.5°C. Cpb = 130.0 J/kg*C and △Hj for lead is 2.04x10^4 J/kg . Say you start at room temperature (25.0°C). How much heat must you transfer to melt all the lead?

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

What are chlorofluorocarbons and what impact do they have on the atmosphere?

The plum pudding model of the atom states that ?