Conductivity and concentrations
To determine the relation between current intensity and concentration of a strong electrolyte solution.
Lo que aprenden los alumnos
La base científica de este experimento
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.
Equipo utilizado
- 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
Productos químicos y reactivos
- Sodium chloride solutions of different concentrations
- Distilled water
Notas de seguridad
- Be careful when using the power supply and conductive solutions: risk of electric shock.
Preguntas para los alumnos
- Which solution conducts more current?
- Why?
Qué puedes esperar
<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>
Eliminación
Dispose of the solutions into the waste container or into the sink.
Realiza este experimento en tu clase
Este experimento forma parte del « Mobile Lab » de ATP, un laboratorio autónomo que convierte un aula normal en un laboratorio de ciencias en pleno funcionamiento, con más de 200 experimentos de física, química, biología, robótica e ingeniería. « Gali », el tutor de IA integrado en ATP Connect, guía a los alumnos paso a paso y responde a sus preguntas en la mesa de trabajo.
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