Groups:
1. Trend of Radius/I.E./E.N.
2. Reaction with water/oxygen/chlorine
3. Decomposition of nitrate and carbonate of Group II
4. Trend of solubility of Group II
The periodic properties of the elements results from the trend of the atomic or ionic properties.
Group的周期性得到了高度统一
Monday, 23 December 2019
Periodicity for Period
Periods:
1. Trend of Radius/I.E./E.A./E.N.
2. Metal and Non-metal (Transferring / Sharing Electrons)
3. Oxide and Chloride (Structure and Physical Properties)
4. Reaction of Oxide and Chloride with water/acid/base
It is a great practice to connect the physical and chemical properties in a series.
物理和化学性质的周期性得到统一
1. Trend of Radius/I.E./E.A./E.N.
2. Metal and Non-metal (Transferring / Sharing Electrons)
3. Oxide and Chloride (Structure and Physical Properties)
4. Reaction of Oxide and Chloride with water/acid/base
It is a great practice to connect the physical and chemical properties in a series.
物理和化学性质的周期性得到统一
Tuesday, 10 December 2019
How to measure melting point and boiling point?
For Melting point:
1. Melting Point Apparatus
2. Thiele Tube Method
For Boiling point:
1. Distillation Method2. Reflux Method
3. Thiele Tube Method
See details @ chem.libretexts.org
Saturday, 30 November 2019
Discussion on A Question (H2, Chem, 2018, P2,Q5(a))
The following is the question.
This question is a very good question, which serves as a bridge between the items (electrochemistry) in syllabus and the application of the theories. But, I would like to discuss two points in this question from my view.
The first question is about the Q5(a)(i), and it involves the conception of reversible electrode. When the external voltage is less than the e.m.f of the cell, it will act as the a Galvanic Cell. When the external voltage is greater than the e.m.f of the cell, it will work as an electrolysis cell (or Electrolytic cell). Moreover, it works similarly to the recharger cell (secondary cell). To tell the truth, this question is very new to students, and it reminds teacher of the reversibility of the electrode.
However, in the next question Q5(a)(ii), the reaction occurs as equation 1, which is spontaneous as the standard cell potential is positive. So the cell should be electrochemistry cell, instead of the electrolysis cell. In the question, it states that 'The Clark Sensor ' is an electrolysis cell. Am I wrong or there is a bug in the question?
Looking forwards to the reply from the professionals who works with the Clark Sensor.
Thanks.
The first question is about the Q5(a)(i), and it involves the conception of reversible electrode. When the external voltage is less than the e.m.f of the cell, it will act as the a Galvanic Cell. When the external voltage is greater than the e.m.f of the cell, it will work as an electrolysis cell (or Electrolytic cell). Moreover, it works similarly to the recharger cell (secondary cell). To tell the truth, this question is very new to students, and it reminds teacher of the reversibility of the electrode.
However, in the next question Q5(a)(ii), the reaction occurs as equation 1, which is spontaneous as the standard cell potential is positive. So the cell should be electrochemistry cell, instead of the electrolysis cell. In the question, it states that 'The Clark Sensor ' is an electrolysis cell. Am I wrong or there is a bug in the question?
Looking forwards to the reply from the professionals who works with the Clark Sensor.
Thanks.
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