Nothing. A molecule is a pure substance if it is of one element.
yes
No, its a compound, which is a pure substance. It is just that molecule and no other molecule, so it is not a mixture.
If it is a pure substance, than only one! Now that pure substance may contain many different elements (as many elements can make up a single pure compound), but a pure substance means only one compound.
Yes. For example water is a pure substance because it is one molecule. Salt is also a pure substance. If you make salt water to rinse your mouth when you have a sore throat, you are rinsing your mouth with a mixture.
Table salt is a pure substance. A pure substance is a substance has one type of molecule and one type of atom. Other pure substance are copper and liquid water.
methane is definatly a pure substance...
Dextrose is a pure substance. It is a simple sugar, also known as glucose, composed of a single type of molecule.
Ethanol is a pure substance, but it is rare to encounter it pure. Laboratory alcohol usually contains small amounts of water and methanol. Alcoholic drinks contain large quantities of water, as well as flavourings.
Molecule, or atom in the case of a pure elemental substance.
Pure Substance.Hg stands for mercury. A pure substance is made of only one type of atom or molecule. Since mercury is an element, it is a pure substance.
Sugar is a pure substance because everything in a sample is alike: a molecule of sugar.
Yes, nitric acid is a pure substance because it consists of only one type of molecule, HNO3.