Page 36 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1 2024-2025

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

Quiz

1- Determine the molarity of a solution made by dissolving 20.0 g of NaOH in
sufficient water to yield a 482 cm solution. (atomic weights H=1 g, O=16
3
g, Na= 23 g)
2- How many grams of potassium dichromate (K 2Cr 2O 7) are required to
prepare a 125 mL solution whose concentration is 1.83 M?

The stoichiometry of reaction in solution

• The calculation of quantities in chemical reactions

“Stoichio” = elements

“metry” = to measure

• It is the quantitative relationships/ratios of reactants
and products involved in a chemical reaction.

• It deals with the ratios in which chemicals react.

• The coefficient in the balanced chemical equation provides the mole ratios
needed to solve stoichiometric problems.

▪ The reaction tells us that mixing two moles of sodium with one mole of
chlorine gas will yield two moles of sodium chloride.

▪ The mole ratio describes the molar ratio at which the reaction will proceed.

▪ The reactants are in a 2:1 molar ratio

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