Chemistry · Grades 9–12
Analytical chemistry · Formula reference 2
Formula reference
Rule and assumptions
Percentage yield
Compare actual pure product with the theoretical maximum in the same units. Yield and purity are different quantities.
yield % = actual/theoretical × 100
Diprotic-acid stoichiometry
Use the balanced equation, not an assumed one-to-one ratio. Here each formula unit supplies two hydroxide ions.
H₂A + 2OH⁻ → A²⁻ + 2H₂O; n(OH⁻) = 2n(H₂A)
Chromatography Rf
Measure both distances from the same origin. Rf is dimensionless and depends on the chromatographic conditions.
Rf = spot distance / solvent-front distance
Linear calibration with a blank
Subtract the intercept or blank first, then divide by the slope. Use the model only within its stated calibration range.
c = (S − b)/m for S = mc + b
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · independent educational and translation review required. Suggested grades are not official curriculum alignment.