Page 41 - Curriculum Visions Dynamic Book

Zinc cup, anode
Manganese nodules
Carbon rod cathode
Manganese oxide corrosion: the slow decay of a substance (MnO2), carbon black resulting from contact with gases and
and ammonium chloride (NH4Cl)
liquids in the environment. The term is often applied to metals. Rust is the corrosion of iron.
precipitate: tiny solid particles formed as a result of a chemical reaction between two liquids or gases.
Manganese oxide in batteries
Manganese oxide is the most commonly used compound of manganese. Under the name of pyrolusite, manganese oxide (a black powder) is bound in with the carbon electrodes of a dry battery.
Manganese oxide “traps” hydrogen gas that is given off as the chemicals of the battery react. In this way the dry battery does not swell up and burst from the formation of hydrogen gas.
The reactivity of manganese
Metals can be arranged in a reactivity series, with the most reactive at the top and the least reactive at the bottom. As you can see, manganese comes above iron in the list and so is more reactive. This means that manganese will remove the oxygen from iron in a heated furnace.
 A dry cell.
Manganese nodules are some of the richest concentrations of any element. The nodules contain mainly manganese and iron oxides, with some other metals such as cobalt and nickel.
The manganese nodules form naturally from metal compounds contained in materials sinking down through sea waters. Near the sea floor the manganese precipitates out of the sea water as small grains. These grains slowly attract more manganese compounds and eventually grow into nodules. At least half the mass of a manganese nodule is made of manganese.
Manganese nodules are found exclusively on
the ocean floor, often lying scattered in huge fields. Each nodule can be the size of a golf ball.
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