Концентрационный элемент

Генерация напряжения из разницы концентраций

Electrochemistry Advanced (University) 45 мин ~$18,00

Цель

Собрать концентрационный элемент из медных полуэлементов с разными концентрациями и проверить предсказание уравнения Нернста для потенциала ячейки.

Предпосылки

A concentration cell generates voltage from the difference in concentration between two otherwise identical half-cells. According to the Nernst equation, the EMF depends on the logarithm of the concentration ratio. This experiment demonstrates that even without different metals, a potential difference arises from entropy-driven mixing.

Предупреждения по безопасности

  • Copper sulfate is toxic
  • Wear gloves when handling solutions

Требуемые СИЗ

goggles gloves lab_coat

Материалы

  • Copper(II) sulfate (CuSO₄) (200 mL total)
    Prepare 0.01M and 1M solutions
  • Copper strips (2) (2 pieces)
    Identical, sanded clean
  • Potassium nitrate salt bridge (1)
    Saturated KNO₃ in agar

Оборудование

Two 250 mL beakers High-impedance voltmeter Wires with alligator clips Sandpaper Volumetric flasks

Процедура

1

Prepare two CuSO₄ solutions: 100 mL of 1.0M and 100 mL of 0.01M.

5 мин Wear gloves
2

Sand both copper strips until shiny and rinse with distilled water.

3 мин
3

Pour the dilute (0.01M) CuSO₄ into one beaker and the concentrated (1.0M) into the other.

2 мин
4

Place one copper strip in each beaker. Connect with the salt bridge.

3 мин
5

Connect the voltmeter. The dilute side is the anode (negative terminal). Measure the EMF.

5 мин
6

Calculate the predicted EMF using the Nernst equation: E = (RT/nF) ln(C_high/C_low) = (0.0257/2) ln(100) = 0.059 V at 25°C.

5 мин
7

Compare measured and theoretical values. Discuss sources of deviation.

5 мин

Ожидаемые результаты

The cell should produce approximately 0.05-0.06 V. The Nernst equation predicts E = (0.02569 V / 2) x ln(1.0/0.01) = 0.059 V at 25°C. Measured values may be slightly lower due to junction potentials.

Уборка

Dispose of copper sulfate waste in designated containers. Rinse and store copper strips. Clean salt bridge.

Детали

Категория
Electrochemistry
Сложность
Advanced (University)
Продолжительность
45 мин
Прим. стоимость
$18,00
Шаги
7
Материалы
3

Ещё эксперименты

Гальваническое покрытие медью 60 min Измерение потенциала гальванической ячейки 60 min Лимонная батарейка 20 min Методы защиты от коррозии 30 min Проверка ряда активности металлов 30 min Сборка элемента Даниэля 45 min Электролиз воды 40 min Электролиз сульфата меди 50 min

Frequently Asked Questions

What is the objective of Концентрационный элемент?
Собрать концентрационный элемент из медных полуэлементов с разными концентрациями и проверить предсказание уравнения Нернста для потенциала ячейки.
How difficult is Концентрационный элемент?
This experiment is rated as Advanced (University). It takes approximately 45 minutes to complete.
What safety precautions are needed for Концентрационный элемент?
Key safety precautions include: Copper sulfate is toxic; Wear gloves when handling solutions.
What materials are needed for Концентрационный элемент?
The main materials required are: Copper(II) sulfate (CuSO₄), Copper strips (2), Potassium nitrate salt bridge.
What results should I expect from Концентрационный элемент?
The cell should produce approximately 0.05-0.06 V. The Nernst equation predicts E = (0.02569 V / 2) x ln(1.0/0.01) = 0.059 V at 25°C. Measured values may be slightly lower due to junction potentials.