Friday, April 17, 2009

Mixed Veg Chow Mein Nutritional Value

The chemical and physical changes

Physical Changes When

materials change shape, trim, stretch, scratch ... physical change occurs. When water changes state, ie to freeze turns to ice, but is still water.

When dissolving a substance in another, a physical change occurs because the substances are not become different ones. For example, when making a soup, it seems that the salt is gone, but still there because when testing stock, sorry. If we want it back, the soup is boiled to evaporate the liquid and see it in the bottom of the pot. When you add sugar to coffee, no longer visible, but the coffee tastes sweet, sugar is still there but dissolved into particles too small to be seen.


Chemical Changes

When you light a candle when it burns the paper, where a bronze statue turns green, when the dough becomes bread ... chemical changes. In all cases listed above, start with some substances and they are transformed into different substances.

smell changes, a sign that some new material has just appeared as a result of chemical transformation of materials that had at first.

color changes indicate that they formed new substances, of a color different from the original.
Questions.
1 .- Notes 5 examples of physical changes and explain why
2 .- Notes 5 examples of chemical changes and explain why