Concept:Guldberg and Waage formulated the Law of Mass Action, standardizing how chemical quantities are expressed in rate and equilibrium equations.
Formula:$$ \text{Active Mass} = [ ] = \frac{n}{V} = \text{Molarity} $$
Solution:- "Active mass" mathematically refers to the molar concentration of a reacting substance.
- Concentration is defined as the number of moles (\( n \)) divided by the volume in cubic decimeters (\( \text{dm}^3 \)).
- Therefore, it means Number of moles per \( \text{dm}^3 \).
- Note: While Option B (moles per liter) is technically identical since \( 1 \text{ dm}^3 = 1 \text{ L} \), SI unit conventions in this curriculum strictly favor \( \text{dm}^3 \), making A the technically 'more correct' textbook answer.
Why other options are incorrect:Grams per \( \text{dm}^3 \) is mass concentration (density), not molar concentration. Simply "moles" ignores the volume requirement entirely.
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