Electrochemical cellsIB MYP Chemistry: Mind map

Exam questions on Electrochemical cells

1. A student makes a simple cell by placing a strip of zinc and a strip of copper in a beaker of sodium chloride solution, and joins the two strips to a voltmeter with wires. The voltmeter shows a reading of about 1 V.
   State the purpose of the sodium chloride solution in the cell.2 marks
2. A student makes simple cells by connecting a copper strip and a strip of a second metal to a voltmeter, with both strips dipped in the same salt solution. The second metal was magnesium in the first cell, zinc in the second and iron in the third. The readings were 2.0 V, 1.1 V and 0.7 V respectively. In every cell the second metal was the negative terminal.
   Describe the pattern in the results.2 marks
3. A car manufacturer in Seoul has developed a car powered by a hydrogen-oxygen fuel cell. Hydrogen from a pressurised tank and oxygen from the air are fed into the fuel cell, which produces the electricity that drives the motor. The only substance leaving the exhaust is water.
   Outline how a hydrogen-oxygen fuel cell produces electricity.3 marks