TESIS

Pangganti.  Esdi, 2012. Class XII science student difficulties SMA District of North Barito Understanding Redox Reactions and Electrochemistry. Thesis. Chemistry Education Studies Program, Graduate Program in Palangkaraya University. Supervisor (I) Prof. Dr. Suandi Sidauruk, M.Pd., and Supervisor (II) Dra. Sriwahyutami, M.Sc.

Keywords: Adversity, Understanding, Redox Reactions and Electrochemistry

ABSTRACT

This study aims to explain the difficulty of class XII science students of SMAN District of North Barito understand and electrochemical redox reactions, including: a) determining the oxidation states of elements in the compound neutral and ionic compounds; b) determine the type of oxidation or reduction reactions; c) determine redox reaction in the event reduction and oxidation processes; d) balance the redox reaction; e) determining if the voltaic cell notation at the anode and cathode reaction produces positive EoSel; and f) specify the use of Faraday’s law of I and II.

The study population was all students in grade XII IPA Barito District State High School North. The sample size in this study that netted as much as 140 to TPRE, and 32 students to test TPRE, the target sample size of 176.
Difficulty understanding the concepts were evaluated using test instruments and understanding of the electrochemical redox reaction (TPRE) along with an interview to locate students’ difficulties in understanding the redox reactions and electrochemistry.

Tryouts for the lowest test scores obtained TPRE students is 3 and the highest scoring students is 13 scale 15. The mean score was 72.0 of 100 students. Index level of difficulty (range 0.38 to 0.63) and different power index (range 0.23 to 0.81) points in the category of ideal matter, it is proved that TPRE test participants’ ability to differentiate. Standard deviation (sd) = 2.62 and = 6.86 S2t and KR-21 = 0.491 rounded to 0.5. Reliability value indicates that the TPRE have good internal consistency, real, and can be trusted to identify students’ difficulties in redox reactions and electrochemistry.

The difference (DB) of each item in the category TPRE about being (all about the TPRE meet the specified criteria is between 0.2 – 0.7), so it can be stated that TPRE used well enough to distinguish students based on ability to respond to items about . The level of difficulty (TK) of each item on TPRE about this, they all meet the established criteria, namely 0.3 to 0.7 (DB tables and TK, attached). That is, every grain of matter is at an ideal level.
The results showed an average score Indicator 1 (Determining the oxidation state of the element in the compound is not charged) of 52.5, Indicator 2 (Determining the oxidation state of the element in the compound charged (ion) of 54.3; Indicator 3 (Specify type of reduction or oxidation reactions) amounting to 55.0; Indicators 4 (Determining the redox reaction, in the event of the reduction process (reduction oxidation state) and the oxidation process (increase in oxidation state)) of 49.6; Indicator 5 (Balance Redox Reactions) of 43.6; Indicators 6 (Determining the notation voltaic cells, if the reaction at the anode and cathode produces positive Eosel) of 46.7; Indicator 7 (Specify the use of Faraday’s law I) of 50.4; and Indicator 8 (Specify the use of Faraday’s law II) of 51.1. so the order of difficulty TPRE (from easy to difficult) based on the indicators are: Indicator 3 (Specify type of reduction or oxidation reactions); Indicator 2 (Determining the oxidation state of the element in the compound charged (ion) Indicator 1 (Determining the oxidation state of the element in the compound is not charged); Indicators 8 ( specify the use of Faraday’s law II); Indicator 7 (Specify the use of Faraday’s law I); Indicators 4 (Determining the redox reaction, in the event of the reduction process (reduction oxidation state) and the oxidation process (increase in oxidation state)); Indicators 6 (Determining the voltaic cell notation, if reaction in anode and cathode produces positive Eosel); and Indicators 5 (Balance Redox Reactions).

In this study identified as many as 20 high school students in trouble and electrochemical redox reactions, namely: (a) Indicator 1, identified two (2) difficulty in determining the oxidation number of students on the elements of uncharged compounds, namely: (1) the oxidation number of elements equal to the number oxidation of compounds, (2) does not include an index in the calculation of the oxidation states of elements, (b) indicator 2, identified 2 (two) students experienced difficulty in determining the oxidation number of elements in the charged compounds, namely: (1) considers the elements oxidation number equal to the charge ion, (2) are not included in the calculation of the oxidation state of the element index, (c) Indicator 3, identified 3 (three) students experienced difficulty in determining determine the type of reduction or oxidation reactions of the half reactions are: (1) can not determine the type of reduction or oxidation reactions, (2) can not determine the oxidation states of elements in the compound, (3) assumes that the charged compounds, the oxidation states equal to the charge; (d) Indicator 4, identified 2 (two) students’ difficulties in determining the redox reaction, in the event of process reduction (reduction oxidation state) and the oxidation process (increase in oxidation state), namely: (1) did not show an increase and decrease in oxidation that takes place simultaneously at a given reaction, (2) can not determine the oxidation state of monatomic ions, (e) Indicator 5, identified 3 (three) to equalize the difficulty of students in the redox reaction is: (1) is unable to determine the conditions of how the H, O, or H2O is added, (2) does not equate to the amount of the charge, (3) does not equate to the number of electrons received by the number of electrons is released; (f) Indicator 6, identified three (3) difficulty in determining students’ voltaic cell notation, if the reaction at the anode and cathode produces positive Eosel, namely: (1) can not demonstrate that the reaction takes place at the anode and cathode to see prices Eo, (2) can not determine the price E0sel, (3) can not determine the order in the cell diagram, (g) Indicator 7, identified two (2) difficulty in determining student I use Faraday’s law, namely: (1) can not determine the changes oxidation, (2) can not determine the valence (e), (h) Indicator 8, identified three (3) difficulty in determining the use of law students Faraday II, namely: (1) can not determine the reactions that take place at the electrodes, (2) can not determine the changes in oxidation state (PBO) or valence (e), (3) can not calculate the weight of sludge produced in the experiment

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