pure substance
a mixture
Neither. Oxygen is an element, which is a pure substance and not a mixture.
Aluminum is an element, a pure substance.
Copper metal is an element and thus a pure substance.
It's an element. So, yes, it's a substance, not a mixture.
quarts is a solid it is a pure substance and it is a element
Pure sugar is a substance (compound).
Calcium is an element and therefore a pure substance.
Oxygen is an element and a pure substance.
Sodium is a pure substance, an Element.
Oxygen is an element indicating that is a pure substance.
Sulfur is not a mixture at all. It is a pure substance. Specifically it is an element.