Answer: element.
Justification:
1) A molecule is the union of two or more atoms.
2) When two or more atoms of different elements bond together, the molecule formed is a compound.
For example: one atoms of hydrogen and one atom of chlorine form the molecule HCl, which is a compound (hydrogen chloride).
3) When the molecules is formed by two atoms of the same element, it is not called a compound, but element. Some examples of this are the diatomic gases:
H₂: hydrogen
Cl₂: chlorine
Br₂: bromine
O₂: oxygen
S₂: sulfur
N₂: nitrogen.
Answer: It is an unsaturated solution
Explanation: This is because it has more solute than a normal solution.
Answer:
B. They are dimensionless ratios of the actual concentration or pressure divided by standard state concentration, which is 1 M for solutions and 1 bar for gases.
Explanation:
Activity of a substance is defined as the ratio of an effective concentration or an effective pressure to a standard state pressure or a standard state pressure. It is usually a unit less ratio.
Concentrations in an equilibrium constant are really dimensionless ratios of actual concentrations divided by standard state concentrations. Since standard states are 1 M for solutes, 1 bar for gases, and pure substances for solids and liquids, these are the units to be used.
Hence, activity is a fudge factor to ideal solutions that correct the true concentration. Activity of a gas and solute concentration is a ratio with no unit.
