1 Each square on the map is 2 cm by 2 cm (4 cm 2) and represents 1 km 2 on the surface of the earth. 2  For 1:25,000 maps, the grid lines are 4 cm apart. 3  Each square on the map is 4 cm by 4 cm (16 cm 2) and represents 1 km 2 on the surface of the earth.
+ 2 e â + 2 H + â. In the last example, H + ions (hydrogen ions) also take part in the reaction, and are provided by an acid in the solution, or by the solvent itself (water, methanol etc.). Electrolysis reactions involving H + ions are fairly common in acidic solutions.
Electrolysis is an example of an endothermic reaction but you can create one easily in the kitchen just by dissolving salt or sugar in water. If you use cold water and lots of salt you can even make ice-cream see our Cool Chemistry blogpost for more details.