Answer : The smallest unit of a substance that behaves like the substance is, molecule.
Explanation :
Pure substance : It is defined as a substance that is made by the combination of only one type of atom or only one type of molecule.
Compound : It is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.
Element : It is a pure substance which is composed of atoms of similar elements.
Molecule : It is the smallest particle in the chemical compound or chemical element or a substance that has the same chemical properties of that compound or element.
Hence, the smallest unit of a substance that behaves like the substance is, molecule.
Missing question: <span>A 5.00 L sample of O2 at a given temperature and pressure contains a 1.08x10^23 molecules. How many molecules would be contained in each of the following at the same temperature and pressure? </span>
a) 5.00 L H2.
<span>b) 5.00 L CO2.
Use </span>Avogadro's Law: The Volume Amount Law: <span>equal </span>volumes<span> of all gases, at the same temperature and pressure, have the same </span>number<span> of molecules. Because hydrogen and carbon(IV) oxide are gases, number of molecules are the same as number of oxygen molecules, so:
a) N(H</span>₂) = 1.08·10²³.
b) N(CO₂) = 1.08·10²³