Preparation of Buffer and Solution
Experiment 3 : Preparation of Solutions and Buffers
Objectives : 1. To study and understand the principle theory and formula of preparation of buffer and solution. 2. To learn the methods of buffer and solution preparation. 3. To focus on concentration units of molarity, percentage of concentration, and dilution of solution.
Introduction :
When a substance, called a solute, is dissolved in another substance, called the solvent, a solution is formed. A solution is known as a homogeneous mixture of two or more substances. For example, vinegar is a solution of acetic acid, the solute, in water, the solvent. A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it. An acidic buffer solution is simply one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts often sodium salt. An alkaline buffer solution has a pH greater than 7. Alkaline buffer solutions are commonly made from a weak base and one of its salts. When hydrogen ions are added to a buffer, they will be neutralized by the base in the buffer. Hydroxide ions will be neutralized by the acid. These neutralization reactions will not have much effect on the overall pH of the buffer solution.
A. Molarity
Molarity is another way of expressing concentration. Molarity is the number of moles in exactly one liter of solution. The unit, therefore are moles per liter, specifically its moles of solute per liter of solution.
Molarity = moles of solute / liter of solution
B. Normality
Normality is usually used to compare solutions based on the basis of its concentration of particular ions. Normality (N) is the number of equivalents of solute per liter of solution. The difference between molarity and normality is that molarity provides information about the number of molecules in a liter of solution and normality provides information about the number of reactive units in a liter of
Objectives : 1. To study and understand the principle theory and formula of preparation of buffer and solution. 2. To learn the methods of buffer and solution preparation. 3. To focus on concentration units of molarity, percentage of concentration, and dilution of solution.
Introduction :
When a substance, called a solute, is dissolved in another substance, called the solvent, a solution is formed. A solution is known as a homogeneous mixture of two or more substances. For example, vinegar is a solution of acetic acid, the solute, in water, the solvent. A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it. An acidic buffer solution is simply one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts often sodium salt. An alkaline buffer solution has a pH greater than 7. Alkaline buffer solutions are commonly made from a weak base and one of its salts. When hydrogen ions are added to a buffer, they will be neutralized by the base in the buffer. Hydroxide ions will be neutralized by the acid. These neutralization reactions will not have much effect on the overall pH of the buffer solution.
A. Molarity
Molarity is another way of expressing concentration. Molarity is the number of moles in exactly one liter of solution. The unit, therefore are moles per liter, specifically its moles of solute per liter of solution.
Molarity = moles of solute / liter of solution
B. Normality
Normality is usually used to compare solutions based on the basis of its concentration of particular ions. Normality (N) is the number of equivalents of solute per liter of solution. The difference between molarity and normality is that molarity provides information about the number of molecules in a liter of solution and normality provides information about the number of reactive units in a liter of