Identical molecules.
A sample of one of the elements consists of atoms of that element.
A sample of a pure compound consists of the same molecules throughout its mass.
By Crystalization
Water (H2O) is a chemical compound.
The population consists of every possible unit where a sample is a subset of the population. Note that population and sample need not refer to persons. For example, if studying biodiversity, the population could consist of plots of land.
a pure substance! ;)
Pure carbon monoxide is a compound, containing equal numbers of carbon and oxygen atoms in any sample of the compound.
Mass of C= 80.0 g Mass of H =20.0 g
a pure substance. :)
Magnesium is an element.it is a compound as it is made up of two elements
compoundIf the iron fillings are pure, they contain only one type of atom (all the atoms have the same number of protons). Thus, the filings would be a sample of the element iron. If the filings are rusty, then they would contain compounds (iron oxides).
A sample that cannot be separated into two or more substances by physical means is a compound. A compound is made up of 2 or more elements which cannot be broken down by physical means.