Answer:
. A closed system allows only energy transfer but no transfer of mass. Example: a cup of coffee with a lid on it, or a simple water bottle. ... In reality, a perfectly isolated system does not exist, for instance hot water in a thermos flask cannot remain hot forever.
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Answer:</h2>
The magnesium ribbon, <u>D. It forms a material to cast the tool mark</u>.
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Explanation:</h2>
When a magnesium ribbon is burnt in the presence of oxygen it gives out strong light and heat is produced. Apart from it, it leads to the production of substance called as magnesium oxide which is formed as the product due to the reaction of magnesium with the oxygen present in the air.
Tool marks are the mark which is created by tools while using them. In order to identify or locate them castes made up of magnesium oxide is utilized. When this is pasted on the suspected area, the tool mark of the suspected tool gets pasted on it.
Answer:
The melting point of a substance is the temperature at which it change state from solid to liquid is called crystallization point.
