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The 8951 one-chip microcomputer (μc) is usually used in communication, controller and measuring instruments .Because of the advantages of its powerful command, large memory capacity and series communication capability. The 8951μc can be used to design the interfaces we need . In this study , a chemical detection system including sensor 、amplifier 、ADC0804、89C51、LCD and RS-232 was prepared . The 8951 microcomputer detection system was applied in chemical experiments such as acid-base titration、hard water determining、and reaction rate. In the acid-base titration experiment;The glass electrode as a sensor, with the 8951μc detection system to measure the titration potential .The signal from 8951μc detection system was transferred to PC with RS-232 interface for signal acquisition and data processing to get titration curve and store the data . The acid-base titration potential was observed as function of titration time . In the precipitation titration experiment ;Various concentrations solution of AgNO3 and NaCl were prepared .In this study, ORP (Oxidation Reduction potential)electrode as a sensor with 8951μc to measure precipitation titration potential . The digital output of 8951 microcomputer detection system was displayed in a LCD(liquid Crystal Display)device. The titration curves was drawn by reading the LCD display . The precipitation titration potential was observed as function of titration time. In the reaction rate experiment;The reaction of thiosulfate with hydrochloric acid was carried out . The purpose of this experiment is to determine the effect of concentration and temperature on the reaction rate. In this reaction, solid sulfur is produced, lead to a cloud solution and the increased CdS photo resistance resulting in the decreased output voltage of CdS. The necessary reaction time and the reaction rate could be estimated from the change in output voltage of CdS. There are three parts in this experiment.(1)The effect of temperature on the reaction rate(2)The effect of concentration of thiosulfate ion on the reaction rate and determine the reaction order of thiosulfate in the reaction and(3)The effect of the concentration of HCl solution on the reaction rate and determine the reaction order of HCl solution in the reaction.
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