Molarity and Normality in Solutions Quiz

Solutions

• A solution is a homogeneous mixture of two or more substances.
• The substance present in a larger amount is called the solvent.
• The substance present in a smaller amount is called the solute.

Concentration

• Molality expresses concentration as moles of solute per 1000 g of solvent.
• Molarity expresses concentration as moles of solute per 1000 ml (1 liter) of solution.
• Normality expresses concentration as gram equivalent weight of solute per 1000 ml (1 liter) of solution.

Moles

• A mole is a unit of measurement used in chemistry to express amounts of a chemical substance.
• One mole of a substance contains 6.022 x 10^23 particles (Avogadro's number).

Molar Mass

• The molecular weight of KCl is 74.55 g/mol (atomic weight of K + atomic weight of Cl = 39.10 g/mol + 35.45 g/mol).

Calculating Moles

• To calculate the number of moles in a given mass of a substance, divide the mass by the substance's molar mass.
• Number of moles of KCl in 81.97 g is 1.1 mol (81.97 g / 74.55 g/mol).

Molarity

• Molarity is defined as the number of moles of solute per liter of solution.
• The molarity of a solution containing 4 moles of HCl in 2 liters of solution is 2 M (4 mol / 2 L).

Preparing Solutions

• To prepare a 0.2 M solution of NaCl using 250 mL, you would dissolve 2.92 g of NaCl in 250 mL of water.
• To calculate the mass of NaCl needed, first calculate the moles of NaCl required for the solution (0.05 mol), then multiply by the molar mass of NaCl (58.44 g/mol).

Dilution

• To calculate the volume of a diluted solution, the equation M1V1 = M2V2 can be used.
• Using this equation, you can calculate that 400 mL of a 0.5 M solution can be made from 100 mL of a 2 M solution.

Test your knowledge of molarity, normality, solvents, solutes, and solution formation with this quiz. Learn about the concepts of mixtures, dilution, and components of solutions.