CHEM 1010H Study Guide - Quiz Guide: Joule, Royal Aircraft Factory F.E.2, Junkers D.I

CHE 114-01 Homework 2 Understanding Standard Entropy of Reaction previous 10 of 10 retum to assignm Understanding Standard Entropy of Reaction Part A Molecular systems tend to move spontaneously to Predict the sign of the entropy change, AS for each of the reaction displayed. a state of maximum randomness or disorder. The measure of the number of energenically equivalent Drag the appropriate items to their respective bins. states is called entropy and is denoted by the symbol S. As a state function, entropy change, AS Reset) (Help) depends only on initial and final states. AS has a positive value when disorder increases and a negative value when disorder decreases. The following conditions usually result in an increase in Pb2+(aq) 2C (aq)-PbCl2(s) 2Nacios (s) 2Naci(s) +302 (g) entropy: a change of phase: solid-liquid-gas an increase in the number of gas ChHs (g) 502 (g)-+3Coh (g) 4 molecules, or a solid dissolving to form a solution. Although the sign of the entropy change can be predicted as described above, the actual value of Negative AS must be calculated from the absolute entropy values, Sa, of the reactants and products: s (products) S (reactants) Submit Hints My Answers Give Up Review Part

The standard heat of formation, Delta H_f degree, is defined as the enthalpy change for the formation of one mole of substance from its constituent elements in their standard states. Thus, elements in their standard states have Delta H_f degree = 0. Heat of formation values can be used to calculate the enthalpy change of any reaction. Consider, for example, the reaction 2NO(g) + O_2(g) 2NO_2(g) with heat of formation values given by the following table. Then the standard heat of reaction for the overall reaction is Delta H_rxn degree = Delta H_f degree (products) - Delat H_f degree (reactants) = 2(33.2) - [2(90.2) + 0] = -114 kJ For which of the following reactions is Delta H_rxn degree equal to Delta H_f degree of the product(s)? You do not need to look up any values to answer this question. Check all that apply. Li(s) + 1/2 F_2 (I) rightarrow LiF(s) C(s, graphite) + O_2(g) rightarrow CO_2(g) 2Li(s) + F_2 (s) rightarrow 2LiF(s) CO(g) + 1/2 O_2(g) rightarrow CO_2 (g) Li(s) + 1/2 F_2 (g) rightarrow LiF(s) BaCO_3(s) rightarrow BaO(s) + CO_2(g) The combustion of propane C_3H_8, occurs via the reaction C_3H_8(g) + 5O_2(g) rightarrow 3CO_3(g) + 4H_3O(g) with heat at formation values given by the following table: Calculate the enthalpy for the combustion of 1 mole of propane. Express your answer to four significant figures and include the appropriate units.