Page 24 - Curriculum Visions Dynamic Book

Compounds of zinc
Most zinc is used in alloys, but zinc compounds also have widespread applications, from pesticides and fungicides to strengtheners in rubber. The special reflective properties
of zinc oxide also make it extremely useful
as harmless paint pigments (instead of lead).
Zinc oxide
Zinc oxide (ZnO) is a common, white compound of zinc. It is prepared by heating zinc in a furnace and then oxidising and finally distilling the vapour.
Zinc oxide has a high refractive index, meaning
that light is reflected from it easily. It is therefore used to provide the colour (pigment) to white paint and to make a white glaze on ceramics. It is also used as one of the components for protecting skin from sunburn.
Zinc oxide is extremely toxic to mildew and fungi, but harmless to people, so it can be used widely in
the home, for example in paints, in wallpaper adhesives and as the foundation for many forms of make-up.
Zinc oxide is also used in rubber. By adding between 3 and 5% zinc oxide to the rubber, curing is made much easier. When used in tyres, it helps to conduct heat away from the rubber so that the tyres do not get too hot. It also increases the strength of the rubber.
 Zinc oxide is used as a sunblock because it is highly reflective. The sunblock shown in the pot and on this skier’s face has been coloured for cosmetic purposes; the sunblock used on the skier’s lips has no added colours.
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