As a scientist, you want to figure out what happens when you put alka-seltzer in water. You open the alka-seltzer tablet and observe that it is white, round and smooth. You take the tablet and crush it into 4 pieces. You fill a glass with tap water and record the temperature of the tap water. It is 51 degrees celsius. Next, you drop the tablet into the water. The water starts bubbling and you hear a fizzing sound. After two minutes, you record the temperature of the water with alka-seltzer tablet and notice that it is now 39 degrees celsius. Identify the physical and chemical changes.

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)