Do elements have only one substance?

Answer 1

'In one phase' is not an essential addition to this statement: 'A pure mixture is one substance', without it is more true.

For example: Ice cubes or crystals in zero degree liquid water is inhomogenous, though it is ONE substance, called water.

Answer 2

The idea of a substance is absolutely basic to understanding chemistry. A single substance means 'one substance on its own'. For instance table sugar is one substance. It's a different substance from salt. Water is a different substance from cooking oil. In everyday life we nearly always deal with substances which are mixed up with others. For instance tap water contains minerals and substances the water companies add for our health, such as chlorine. It is possible to separate the water from all these 'extras', for instance by distilling it, and then you have just water, one substance on its own. If we have just one substance we say it is 'pure'. (We have to be careful not to use 'pure' in its many everyday meanings when we are doing chemistry). We meet very few pure substances in the world around us. Table sugar is the easiest to find. Even household salt usually has traces of other substances added to help it to flow smoothly. If we study mixtures it is hard to know which part is doing what, so some of the first things we learn in chemistry lessons are the techniques for separating mixtures so we can get single substances.

Answer 3

It may have a single substance, but can also have more than one substance

Answer 4

no because it has different characteristics

Answer 5

The answer is simple; a pure substance (compound) !

Answer 6

No. Most substances can be solids, liquids, or gases given the right conditions. Water is the only substance that can be present in all three phases at conditions found on the earth.