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Explain why a water or carbon dioxide fire extinguisher might not be effective in putting out a sodium fire.
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Chemical Principles
- From the data given in Appendix I, determine the standard enthalpy change and the standard free energy change for each of the following reactions: (a) BF3(g)+3H2O(l)B(OH)3(s)+3HF(g) (b) BCl3(g)+3H2O(l)B(OH)3+3HCl(g) (c) B2H6(g)+6H2O(l)2B(OH)3(s)+6H2(g)arrow_forwardFrom data in Appendix 4, calculate H, S, and G for each of the following reactions at 25C. a. CH4(g) + 2O2(g) CO2(g) + 2H2O(g) b. 6CO2(g)+6H2O(l)C6H12O6(s)Glucose+6O2(g) c. P4O10(s) + 6H2O(l) 4H3PO4(s) d. HCl(g) + NH3(g) NH4Cl(s)arrow_forwardThe reaction of quicklime, CaO, with water produces slaked lime, Ca(OH)2, which is widely used in the construction industry to make mortar and plaster. The reaction of quicklime and water is highly exothermic: CaO(s)+H2O(l)Ca(OH)2(s)H=350kJmol1 (a) What is the enthalpy of reaction per gram of quicklime that reacts?. (b) How much heat, in kilojoules, is associated with the production of 1 ton of slaked lime?arrow_forward
- The thermochemical equation for the burning of methane, the main component of natural gas, is CH4(g)+2O2(g)CO2(g)+2H2O(l)H=890kJ (a) Is this reaction endothermic or exothermic? (b) What quantities of reactants and products are assumed if H = 890 kJ? (c) What is the enthalpy change when 1.00 g methane burns in an excess of oxygen?arrow_forwardThe first step in the preparation of lead from its ore (galena, PbS) consists of roasting the ore. PbS(s)+32O2(g)SO2(g)+PbO(s) Calculate the standard enthalpy change for this reaction, using enthalpies of formation (see Appendix C).arrow_forwardThe first step in the production of nitric acid from ammonia involves the oxidation of NH3. 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) (a) Use standard enthalpies of formation to calculate the standard enthalpy change for this reaction. (b) How much energy is evolved or absorbed as heat in the oxidation of 10.0 g of NH3?arrow_forward
- When lightning strikes, the energy can force atmospheric nitrogen and oxygen to react to make NO: N2(g)+O2(g)2NO(g)H=+181.8kJ (a) Is this reaction endothermic or exothermic? (b) What quantities of reactants and products are assumed if H = +181.8 kJ? (c) What is the enthalpy change when 3.50 g nitrogen is reacted with excess O2(g)?arrow_forwardThe enthalpy change for the following reaction is 393.5 kJ. C(s,graphite)+O2(g)CO2(g) (a) Is energy released from or absorbed by the system in this reaction? (b) What quantities of reactants and products are assumed? (c) Predict the enthalpy change observed when 3.00 g carbon burns in an excess of oxygen.arrow_forwardCalculate H for the reaction N2H4(l)+O2(g)N2(g)+2H2O(l) given the following data: Equation H(KJ) 2NH3(g)+3N2O(g)4N2(g)+3H2O(l) 1010 N2O(g)+3H2(g)N2H4(l)+H2O(l) 317 2NH3(g)+12O2(g)N2H4(l)+H2O(l) 143 H2(g)+12O2(g)H2O(l) 286arrow_forward
- The Romans used calcium oxide, CaO, to produce a strong mortar to build stone structures. Calcium oxide was mixed with water to give Ca(OH)2, which reacted slowly with CO2 in the air to give CaCO3. Ca(OH)2(s) + CO2(g) CaCO3(s) + H2O(g) (a) Calculate the standard enthalpy change for this reaction. (b) How much energy is evolved or absorbed as heat if 1.00 kg of Ca(OH)2 reacts with a stoichiometric amount of CO2?arrow_forwardEstimate H for the following reactions using bond energies given in Table 8.5. 3CH2=CH2(g) + 3H2(g) 3CH2CH3(g) The enthalpies of formation for C6H6(g) and C6H12 (g) are 82.9 and 90.3 kJ/mol. respectively. Calculate H for the two reactions using standard enthalpies of formation from Appendix 4. Account for any differences between the results obtained from the two methods.arrow_forward
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