An ideal gas sealed in a rigid 3.58-L cylinder, initially at pressure Pi=10.20 atm, is cooled until the pressure in the cylinder is Pf=1.22 atm. What is the enthalpy change for this process?

In a coffee cup calorimeter, 50.0 mL of 1.00 M NaOH and 50.00 mL of 1.00 M HCl are mixed. Both solutions were originally at 24.6 C. After the reaction, the final temperature is 31.3 C. Given that the density of NaCl solution is 1.038 g/mL and the specific heat of NaCl solution is 3.87, calculate the change in enthalpy of neutralization per mole for the reaction of HCl with NaOH. Assume that no heat is lost to the surroundings.

6 8 7. Consider the following reaction: 2 CH;OH (g) → 2 CH4() O2 (g), AH = + 252.8 kJ a) Is this reaction exothermic or endothermic? b) Calculate the amount of heat transferred when 26.0 g of CH3OH(g) is decomposed by this reaction at constant pressure. Express the heat to three significant digits with the appropriate units. c) For a given sample of CH;OH, the enthalpy change during the reaction is 82.9 kJ. What mass of methane gas is produced? Express the mass to three significant digits with the appropriate units. d) How many kilojoules of heat are released when 38.8 g CH4(g) reacts completely with 02(g) to form CH,OH(g) at constant pressure?

150.0 mL of dilute hydrochloric acid is placed in a coffee cup calorimeter. The initial temperature of the solution is recorded to be 14.5°C. A piece of magnesium ribbon of mass 0.575 g is placed in the solution and allowed to react. If the molar enthalpy change for this reaction is -584 kJ/mol, what final temperature would you predict?