lgs everything else). e system (the part you are studyml (reaut nsi ost systems we are interested in will have a constant pressure, mean ing that q (heat or thermal energy) would be equivalent to the change in enthalpy (AH) We defined environments in which heat goes into the system surroundings get hot as exothermic ΔΗ- and the surroundings get cold as EX rmic AH + while environments in which heat goes out of the system and the For each of the environments below: (1) identify your system and surroundings and (2) predict whether it would be endothermic or exothermic. 1. a. Wood burning b. Water freezing c. Sweat evaporating d. Chemical hand-warmer

Thermochemistry is a branch of chemistry that qualitatively and quantitatively describes the energy changes that occur during chemical reactions. AH(T.) Products AH"(T) Reactants T, Temperature, T (i) Which Law of Thermochemistry is illustrated in the graph above (ii) Accurately define this Law with aid of appropriate equation/s. Enthalpy, H

A student runs two experiments with a constant-volume "bomb" calorimeter containing 1300. g of water (see sketch at right). thermometer stirrer First, a 6.000 g tablet of benzoic acid (C,H,C0,H) is put into the "bomb" and burned completely in an excess of water oxygen. (Benzoic acid is known to have a heat of combustion of 26.454 kJ/g.) The temperature of the water is insulation observed to rise from 13.00 °C to 40.13 °C over a time of 10.0 minutes. Next, 5.200 g of ethane (C,H) are put into the "bomb" and similarly completely burned in an excess of oxygen. This time the temperature of the water rises from 13.00 °C to 53.96 °C. chemical reaction "bomb" Use this information, and any other information you need from the ALEKS Data resource, to answer the questions below about this reaction: A "bomb" calorimeter. 2C,H,(g) + 70,(g) 4CO,(g) + 6 H,0 (g) Be sure any of your answers that are calculated from measured data are rounded to the correct number of significant digits. Note for advanced…

and 2 Enthalpy #1.30 enoindice pled TT 2010 2D49.bs 22) When 1 mole of Fe2O3(s) reacts with H₂(g) to form Fe(s) and H2O(g) according to the following equation, 98.8 kJ of energy are absorbed. (6 Fe2O3(s) + 3 H2(g) → 2 Fe(s) + 3 H₂O(g) (pp) (20/d4 (pm) $40 D Reaclanis 13:48 SH Products endothermic, A endothermic, B (2) exothermic, A exothermic, B nad W (21 Enthalpy MOMS. Reactants Products (A) (B) Is the reaction endothermic or exothermic, and which of the enthalpy diagrams above represents grow olor and to noin (01 this reaction? SH GH TH A HOMH X HILD 08.10 Page 6 of 8