Answer: when reactants and products are gases at STP.
Justification:
1) STP stands for standard temperature (0°) and pressure (1 atm).
2) According to the kinetic molecular theory of the gases, and as per Avogadro's principle, equal volumes of gases, at the same temperature and pressure, have the same number of molecules.
3) Since the coefficients in a balanced chemical equation represent number of moles, when reactants and products are gases at the same temperature and pressure, the mole ratios are the same that the volume ratios, and then the coefficients of the chemical equation represent the volume ratios.
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.
In order to synthesize a complex organic molecule, the
chemist should at least illustrate or imagine the bonds that are in need to be
cut down or to separate in order to obtain the compound that can be easily
changed.
Strong acid is your answer
