One of the most efficient heat engines ever built is a coal-fired steam turbine in the Ohio River valley, operating between 1 87
0°C and 430°C. (a) What is its maximum theoretical efficiency? %
(b) The actual efficiency of the engine is 42.0%. How much mechanical power does the engine deliver if it absorbs 1.30 105 J of energy each second from its hot reservoir?
No chemical bonds are broken or formed in melting butter, so it is not a chemical change. The melting process is only a physical change, the change of state from solid to liquid.
