Measurements show that the energy of a mixture of gaseous reactants increases by 396. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 122. kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction. Be sure your answer has the correct number of significant digits. O exothermic ? Is the reaction exothermic or endothermic? O endothermic

As a system increases in volume, it absorbs 55.0 J of energy in the form of heat from the surroundings. The piston is working against a pressure of 0.540 atm. The final volume of the system is 58.2 L. What was the initial volume of the system if the internal energy of the system decreased by 103.4 J?

Measurements show that the energy of a mixture of gaseous reactants decreases by 373. kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 136. kJ of work is done on the mixture during the reaction. Calculate the change in enthalpy of the gas mixture during the reaction. Round your answer to 3 x10 significant digits. exothermic Is the reaction exothermic or endothermic? endothermic

A 56.5 g sample of iron is put into a calorimeter (see sketch at right) that contains 300.0 g of water. The iron sample starts off at 86.7 °C and the temperature of the water starts off at 21.0 °C. When the temperature of the water stops changing it's 22.8 °C. The pressure remains constant at 1 atm. Calculate the specific heat capacity of iron according to this experiment. Be sure your answer is rounded to 2 significant digits. J 0₂-C x10 x thermometer insulated container water sample a calorimeter

a You want to determine the value for the enthalpy of formation of CaSO4(s). Ca(s) + S(s) + 2 O₂ (g) → CaSO4(s) This reaction cannot be done directly. You know, however, that both calcium and sulfur react with oxygen to produce oxides in reactions that can be studied calorimetrically. You also know that the basic oxide CaO reacts with the acidic oxide SO3 (g) to produce CaSO4(s) with A₁ H° = -402.7 kJ. Outline a method for determining A₁H˚ for CaSO4(s), and identify the information that must be collected by experiment. Using enthalpy of formation data, confirm that AƒH° for CaSO4(s) = −1433.5 kJ/mol. What compound is formed when Ca and O2 react?