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Calculate the kilojoules of heat released per gram of the compound reacted with oxygen. The standard enthalpy of formation of
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- 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_forwardWater gas, a mixture of carbon monoxide and hydrogen, is produced by treating carbon (in the form of coke or coal) with steam at high temperatures. (See Study Question 83.) C(s) + H2O(g) CO(g) + H2(g) Not all of the carbon available is converted to water gas since some is burned to provide the heat for the endothermic reaction of carbon and water. What mass of carbon must be burned (to CO2 gas) to provide the energy to convert 1.00 kg of carbon to water gas?arrow_forwardWhat mass of acetylene, C2H2(g), must be burned to produce 3420 kJ of heat, given that its enthalpy of combustion is 1301 kJ/mol? Compare this with the answer to Exercise 5.91 and determine which substance produces more heat per gram.arrow_forward
- A rebreathing gas mask contains potassium superoxide, KO2, which reacts with moisture in the breath to give oxygen. 4KO2(s)+2H2O(l)4KOH(s)+3O2(g) Estimate the grams of potassium superoxide required to supply a persons oxygen needs for one hour. Assume a person requires 1.00 102 kcal of energy for this time period. Further assume that this energy can be equated to the heat of combustion of a quantity of glucose, C6H12O6, to CO2(g) and H2O(l). From the amount of glucose required to give 1.00 102 kcal of heat, calculate the amount of oxygen consumed and hence the amount of KO2 required. The ff0 for glucose(s) is 1273 kJ/mol.arrow_forwardHow many kilojoules of heat will be released when exactly 1 mole of iron, Fe, is burned to form Fe2O3(s) at standard state conditions?arrow_forwardThe standard enthalpy of formation of solid barium oxide, BaO, is 553.5 kJ/mol, and the standard enthalpy of formation of barium peroxide, BaO2, is 634.3 kJ/mol. (a) Calculate the standard enthalpy change for the following reaction. Is the reaction exothermic or endothermic? 2 BaO2(s) 2 BaO(s) + O2(g) (b) Draw an energy level diagram that shows the relationship between the enthalpy change of the decomposition of BaO2, to BaO and O2, and the enthalpies of formation of BaO2(s) and BaO2(s).arrow_forward
- One step in the manufacturing of sulfuric acid is the conversion of SO2(g) to SO3(g). The thermochemical equation for this process is SO2(g)+12O2(g)SO3(g)H=98.9kJ The second step combines the SO3 with H2O to make H2SO4. (a) Calculate the enthalpy change that accompanies the reaction to make 1.00 kg SO3(g). (b) Is heat absorbed or released in this process?arrow_forwardGraphite is burned in oxygen to give carbon monoxide and carbon dioxide. If the product mixture is 33% CO and 67% CO2 by mass, what is the heat from the combustion of 1.00 g of graphite?arrow_forwardAlthough the gas used in an oxyacetylene torch (Figure 5.7) is essentially pure acetylene, the heat produced by combustion of one mole of acetylene in such a torch is likely not equal to the enthalpy of combustion of acetylene listed in Table 5.2. Considering the conditions for which the tabulated data are reported, suggest an explanation.arrow_forward
- The 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 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_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_forward
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