<span>A melting point is the characteristic physical property of a substance. So melting point analysis is one of the simplest and most useful techniques for identifing of a chemical substance. Melting point analysis can also provide information about the purity of a sample. A substance containing soluble impurities usually melts at a lower temperature than the pure compound. It can also melt over a wide range of temperatures. The smaller the range of melting temperatures, the higher the purity of the sample.</span>
About 4 C to for water density until it is cooled
Answer:
C.
Explanation:
Phase change is physical.
Answer:
Magnesium atom, Mg is oxidized
Explanation:
This is because it loses electrons to form msgnesium ion.
The correct answer is:
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" F and Br , because they are in the same group" .
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Note:
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Choice [B]: "F and Br ; because they are in the same period" ; is incorrect; since "F" and "Br" are not in the same "period" (that is, "row").
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Choice [C]: "Na and Mg; because they are in the same group {"column"} ; is incorrect; since: "Na" and "Mg are NOT in the same group {"column"].
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Choice [D]: "Na and Mg" ; because they are in the same period {"row"}; is incorrect. Note: "Na" and "Mg" are, in fact, in the same period {"row"}. However, as aforementioned, {Mg and Na} are not in the same group {"column".}.
Note: The similiarities in physical and chemistry properties among elements are determined and organized — or tend to be so—by "groups" {"columns"} — NOT by "periods" {rows}.
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