At the end of this lab, students should know...
전기화학은 화학 반응과 전기 에너지 사이의 관계를 연구하는 화학의 한 분야입니다.
전기화학 셀은 전해질 용액을 포함하는 반응 챔버(또는 챔버), 염교, 전기적으로 연결된 두 개의 전도성 전극(양극 및 음극)으로 구성됩니다.
산화-환원 반응 또는 산화 환원 반응은 한 쌍의 반쪽 반응으로, 전자는 산화 중에 한 종에서 손실되고 환원 중에 다른 종에 의해 얻어집니다. 환원은 음극에서 발생하고 산화는 양극에서 발생합니다.
출처: Smaa Koraym at Johns Hopkins University, MD, USA
여기에서는 10명의 학생이 짝을 지어 작업하는 실험실 준비 과정을 보여주며, 약간의 과잉이 있습니다. 필요에 따라 수량을 조정하십시오.
| 빨간색과 검은색 리드가 있는 1 멀티미터 |
| 2 앨리게이터 클립 |
| 1 유리 온도계 |
| 1 6웰 반응 플레이트 |
| 집게 1쌍 |
| 1 20mL 부피 플라스크 |
| 1 100mL 부피 플라스크 |
| 1 1mL 부피 피펫 |
| 1 2mL 용량 피펫터 |
| 3 100mL 비커 |
| 1 10mL 눈금 실린더 |
| 1 50mL 눈금 실린더 |
| 1 600mL 비커 |
| 2 유리 깔때기 |
Q1: How do you prepare a 0.1 M oxalic acid solution for a galvanic cells lab?
Weigh 6.304 g of oxalic acid dihydrate and transfer it to an Erlenmeyer flask. Add 500 mL of deionized water, then stir until homogeneous. Use a powder funnel to transfer the solution to a labeled polyethylene bottle and store it in the instructor's hood. Handle oxalic acid with caution as it is corrosive.
Q2: What materials are needed to prepare a salt bridge for a galvanic cell experiment?
Cut string into 2-inch pieces, with three pieces needed per group. Soak the strings in a 0.1 M potassium nitrate solution for one hour before the lab begins. This prepares the salt bridge, which maintains electrical neutrality between the two half-cells in the galvanic cell.
Q3: How should metal electrodes be prepared before use in a galvanic cells experiment?
Cut copper sheet into 2 x 9 cm pieces, zinc sheet into 2 x 6 cm pieces, and silver sheet into 2 x 6 cm pieces. Store each metal type in labeled beakers corresponding to unknown numbers. Clean metal surfaces with emery paper cut into 1 x 2 inch pieces to remove oxidation before assembly.
Q4: What is the correct procedure for preparing unknown solutions in a galvanic cells lab?
Prepare 0.05 M zinc sulfate by weighing 3.6 g and dissolving in 250 mL deionized water. Prepare 0.22 M silver nitrate by weighing 9.34 g and dissolving in 250 mL deionized water. Divide each solution into two brown glass bottles labeled with corresponding unknown numbers and store in the instructor's hood.
Q5: What equipment should be set up at each lab station for a galvanic cells experiment?
Each station requires a multimeter with leads, alligator clips, glass thermometer, 6-well reaction plate, forceps, volumetric flasks, graduated cylinders, beakers, glass funnels, and a 20-mL volumetric flask. These tools enable students to measure solutions, monitor voltage, and assemble electrochemical cells for data collection.
Q6: How do you prepare the potassium nitrate solution for the salt bridge?
Weigh 2.53 g of potassium nitrate and transfer to a flask. Add 250 mL of deionized water and stir until homogeneous. Transfer the 0.1 M solution to a labeled glass bottle and store in the instructor's hood. Use this solution to soak salt bridge strings one hour before the lab.
Q7: What safety and waste management procedures are required for a galvanic cells lab?
Wear appropriate personal protective equipment including a lab coat, chemical splash goggles, and gloves. Handle oxalic acid with caution as it is corrosive. Dedicate a 20-L container for heavy metal waste and ensure it is accessible in the hood for safe disposal of all metal-containing solutions and materials.