A mixture of gaseous reactants is put into a cylinder, where a chemical reaction turns them into gaseous products. The cylinder has a piston that moves in or out, as necessary, to keep a constant pressure on the mixture of 1 atm. The cylinder is also submerged in a large insulated water bath. (See sketch at right.) From previous experiments, this chemical reaction is known to absorb 171. kJ of energy. The position of the piston is monitored, and it is determined from this data that the piston does 336. kJ of work on the system during the reaction. Is the reaction exothermic or endothermic? Does the temperature of the water bath go up or down? Does the piston move in or out? Does heat flow into or out of the gas mixture? How much heat flows? Be sure your answer has the correct number of significant digits. exothermic endothermic up Odown Oneither in Ⓒout Oneither in out Oneither x10 X S 1 atm pressure gases piston cylinder water bath

A 10.7 g sample of aluminum at 85.3 0C is added to 117 mL of water initially at 14.6 0C. Assuming no heat is lost to the surroundings, calculate the final temperature of the system.

A coin dealer, offered a rare silver coin, suspected that it might be a counterfeit nickel copy. The dealer heated the coin, which weighed 16.0 g to 100°C in boiling water and then dropped the hot coin into 29.0 g of water at T = 18.0°C in an insulated coffee-cup, and measured the rise in temperature. If the coin was really made of silver, what would the final temperature of the water be (in °C)? (for nickel, s = 0.445 J/g°C; for silver, s = 0.233 J/g°C )

Every day a certain amount of water evaporates from Earth’s oceans, lakes, and land surface and forms water vapor and clouds in the atmosphere. Every day a certain amount of rain falls back to Earth. Make the reasonable assumption that, on average, the energy absorbed by the evaporation and lifting of the water is equal to the energy released by its condensation and falling back to earth. The evaporation of one mole of water requires approximately 40.6×103 J of heat. An equal amount of heat is released when a mole of water condenses. The annual volume of rainfall on Earth is approximately 4.9×105 km3 and the average cloud altitude is 8.9 km above Earth’s surface. How much energy, in joules, is required every day to evaporate and lift the water?