how is a substance different from a mixture short answer
Answers
Answer:
a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.
Answer:
A substance (in its strictly chemical meaning) has an identity which is given by structure (constant and homogeneous at some microscopic or molecular level), composition (constant) and a set of fixed properties. It turns out that constant composition and most of the characteristic properties of the substance are determined by the specific structure (way of aggregation of the repeating units: atoms or ions). Differently from other answers, we can talk about a given substance even if mixed among other substances. Water substance and sodium chloride substances are actually present in seawater, whereas seawater is a mixture of these and other substances (without being a substance), with variable composition and, consequently, variable properties. So you can simply think of a mixture as a mix of substances with various possible compositions and sets of gradually variable properties. This is very different and more sophisticated of what is “constituent” in a compound substance. A chemical compound is a substance made up of different elements (physically: element atoms), but this does not mean that that substance is made of other (elemental) substances in the same sense a mixture is made of several substances. There is neither hydrogen nor oxygen substances mixed up into water. The only substance present in water is… water and that water is completely different from a gaseous mixture, potentially explosive, of hydrogen and oxygen substances.