Carbon dioxide reduction equilibria constant

One reaction that occurs in producing steel from iron ore is the reduction of iron(II) oxide by carbon monoxide to give iron metal and carbon dioxide. The equilibrium constant Kp for the reaction at 1000 K is 0.259. 

A study of the velocity of reduction of carbon dioxide by carbon at 850° C. shows that the reaction is monomoleeular, and the same is true for the reverse reaction, namely the decomposition of carbon monoxide, which, however, proceeds 166 times more slowly. Undoubtedly, therefore, the reactions arc essentially surface phenomena, the rates varying directly with the partial pressure of the gas in either case. Since the decomposition of carbon monoxide is accompanied by a reduction m volume, increase of pressure should facilitate the reaction at constant temperature, and shift the equilibrium... 

Producer gas is made by the reduction of carbon dioxide to carbon monoxide by carbon. With the total pressure 1 atmosphere, the equilibrium mixture of the two oxides at 1123° C contains 93.77 percent by volume of carbon monoxide, and 6.23 percent of carbon dioxide. What is the equilibrium constant for this reaction at this temperature What would be the composition of the mixture in equilibrium at this temperature if the total pressure ivere 2 atm ... 

The reverse of this reaction, the reduction of carbon dioxide by carbon to form carbon monoxide is of considerable industrial importance being involved in the manufacture of producer gas, etc., and lias been carefully studied. The free energy change of this reaction is such that the equilibrium constant becomes equal to 1 at a temperature of about 1000° K (727° C.). Thus for the reaction ... 

Equation (3-13) shows that the equilibrium pH of the bicarbonate buffer system of plasma can be to some extent controlled by varying the partial pressure of carbon dioxide in the air to which the blood is exposed (i.e. in the lungs). Reduction in partial pressure results in carbon dioxide leaving the blood with a rise in the last term of Equation (3-13) provided that the bicarbonate concentration remains constant. The equilibrium pH of the buffer system and hence the pH of the blood consequently rise. Conversely an increase in partial pressure of carbon dioxide in the alveolar air will result in a fall in the pH of blood plasma. In practice the partial pressure of carbon dioxide in the alveolar air is controlled by the rate of pulmonary ventilation in relation to the rate of production of carbon dioxide by metabolic oxidation within the body. Increased ventilation (i.e. hyperventilation) will lower the partial pressure of carbon dioxide and raise the blood pH, while decreased ventilation raises the partial pressure, making the blood more acid (metabolic acidosis). Normally the respiratory centre controls the rate of ventilation to keep the partial pressure of carbon dioxide close to the normal value of 40 mmHg. 

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