Water can undergo the following dissociation reaction to produce hydrogen ion H + and hydroxide ion OH, and the equilibrium constant of the dissociation reaction is Kw=|H + ||OH - | The equilibrium constant can be correlated with the standard free energy of the reaction by the following formula In the formula, R is a molar gas constant = 8.3143 J ∕ (mol·K); and T is an absolute temperature. The standard free energy of the water dissociation reaction can be calculated as follows According to this, the dissociation constant Kw of water at 25 ° C can be obtained: In pure water, the activities of hydrogen ion H + and hydroxide ion OH - are equal. The condition for obtaining the ionization balance of water is pH=-7.00 (1) The water itself is only stable over a limited potential range, beyond which oxygen or hydrogen is evolved. The upper limit of the water stable zone can be determined by the reduction reaction of oxygen When the oxygen fugacity is 1, that is, the actual target oxygen partial pressure is 1 atm, E=1.229-0.0592pH (3) Similarly, the lower limit of the water stable zone can be determined by the following half-cell reaction. The E Θ =0 of this reaction, so When the hydrogen fugacity is 1 E=-0.0592pH (6) The equilibrium relations (1), (3) and (6) are plotted on the Eh-pH coordinate system as shown in Fig. 1. A straight line parallel to the Eh axis and two parallel lines with a slope of -0.0592 are obtained, 25 ° C The distance between the lower two diagonal lines is 1.229V. For a straight line, just find two points. For the convenience of drawing, the potential values ​​of pH equal to 0 and 10 can be determined separately. If the equilibrium pressure of hydrogen and oxygen is not 1 atm, then two sets of parallel lines with a slope of -0.0592 are obtained on the graph for different equilibrium pressures. Figure 1 Electrochemical equilibrium diagram of water (298K, P O2 =0.29atm) Flat Top Tower Crane, also known as Topless Tower Crane, has the advantages of quick and easy assembly. Usually many Flat Top cranes have been used on construction projects or near airports where overhead clearance is frequently a concern. BQ models of flat top tower crane are 8T Flat Top Tower Crane GHP5517-8 and GHP6016-8; 10T Flat Top Tower Crane GHP6016-10, GHP6518-10 and GHP 6520-10;12T Flat Top Tower Crane GHP6520-12 and GHP7524-12; 16T Flat Top Tower Crane GHP7524-16,ect. Flat Top Crane,FlatTop Tower Crane,Flat Top Type Tower Crane,10T Flat Top Tower Crane,Flat Top Tower Crane Advantages SHEN YANG BAOQUAN BUSINESS CO., LTD , https://www.sytoplesstowercrane.com
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