17. Which of the following lists contains only elements and a reason why they are elements
C12, H2, Na, He - Substances are elements because they are pure.
H, O, NaCl, N2, CO2-Substances are elements because they
contain more than one chemical symbol
Kr, Ne, Ar, He - Substances are elements because they are all noble
gases.
F3, Os, Li, H-Substances are elements because they all have
chemical symbols.

if the concentration of products is decreased, the equilibrium will shift toward the products). add an inert gas (one that is not involved in the reaction) to the constant-volume reaction mixture: this will increase the total pressure of the system, but will have no effect on the equilibrium condition.

explanation:

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.