الصفحة الرئيسيةالتجارب
Conductivity and concentrations
الكيمياء

Conductivity and concentrations

To determine the relation between current intensity and concentration of a strong electrolyte solution.

الكيمياء الكهربائية
conductivity; concentration; strong electrolytes

ما يتعلمه الطلاب

الجانب العلمي وراء هذه التجربة

Substances that dissociate into ions are called electrolytes. Acids, bases and salts are electrolytes, and their aqueous solutions conduct an electric current. Sodium chloride as a crystal does not conduct, but dissolved in water its Na+ and Cl− ions allow current to flow.

المعدات المستخدمة

  • Digital multimeter — 2275.10
  • DC power supply
  • 1 × Connecting wire, red — 2522.03-04
  • 1 × Connecting wire, black — 2522.04-08
  • 2 × Crocodile clips — 2531.52
  • 4 × Copper electrodes — 4716.21
  • 2 × Test cell covers — 4718.10

المواد الكيميائية والمواد الكاشفة

  • Sodium chloride solutions of different concentrations
  • Distilled water

ملاحظات السلامة

  • Be careful when using the power supply and conductive solutions: risk of electric shock.

أسئلة للطلاب

  • Which solution conducts more current?
  • Why?

ما يمكن توقعه

<p>0 A current is measured testing distilled water because distilled water does not conduct electricity.</p><p>Current increases according to the concentration because of the increasing amount of ions present in the solution. A higher value of current is measured every time the solution is replaced with a more concentrated one.</p><p>As concentration increases a greenish colour appears (due to formation of copper ions in solution) and some bubbles may appear (due to the formation of chlorine gas) at the electrodes.</p><p>At the cathode (–), some formation of hydrogen occurs because of the reduction of water. At the anode (+), some formation of chlorine occurs because of the oxidation of chloride ions.</p>

التخلص

Dispose of the solutions into the waste container or into the sink.

قم بإجراء هذه التجربة في فصلك الدراسي

تُعد هذه التجربة جزءًا من برنامج «مختبر العلوم المتنقل» (ATP) Mobile Lab — وهو مختبر متكامل يحول الفصل الدراسي العادي إلى مختبر علوم فعال، ويضم أكثر من 200 تجربة في مجالات الفيزياء والكيمياء والبيولوجيا والروبوتات والهندسة. ويقوم « Gali » — وهو المعلم الذكي المدمج في موقع ATP Connect — بتوجيه الطلاب خلال كل خطوة والإجابة على أسئلتهم أثناء إجراء التجارب.

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