Acid, Base and Salt

Dilution is a process of adding water to the standard solution lowered the concentration of the solution. In dilution of solution, we should take note that mole of solute before dilution is equal to the mole of solute after dilution. Number of mol of solute before dilution = Number of mole of solute after dilution … Read more

Preparing Standard Solutions A standard solution is a solution in which its concentration is known. The steps taken in preparing a standard solution are: Determine the voloume and concentration that you want to prepare. Calculate the mass of solute needed to give the required volume and concentration. Weigh the solute Dissolve the solute completely dissolved … Read more

Concentration of Acid We have learned that the acidity of a solution is owing to the presence of hydrogen ions in a solution. We need to distinguish between the concentration of acid and the concentration of hydrogen ions of an acid. In most cases, the concentration of hydrogen ions has greater significant than the concentration … Read more

Molarity and the pH Value of Acid or Alkali The table below shows the pH value and the molarity of a strong acid and a weak acid. Molarity of Acids pH value Hydrochloric acid Ethanoic Acid 0.1 mol dm-3 1.0 2.9 0.01 mol dm-3 2.0 3.4 0.001 mol dm-3 3.0 3.9 0.0001 mol dm-3 4.0 … Read more

Number of mole of solute in a solution can be calculated by using the following formula[n = frac{{MV}}{{1000}}]n = number of mole of soluteM = molaruty of the solutionV = volume of the solution in cm3 Example:How many moles of zinc sulphate is present in 200cm3 of 0.1 mol dm-3 zinc sulphate solution? Answer:Molarity, M … Read more

Conversion of the Unit of Concentration The chart above shows how to convert the units of concentration from g dm-3 to mol dm-3 and vice versa. The molar mass of the solute is equal to the relative molecular mass of the solute. Example 1:The concentration of a Potassium chloride solution is 14.9 g dm-3. What … Read more

Concentration of a Solution The concentration of a solution tells you how much solute is dissolved in 1 unit volume of solution. The volume of a solution is measured in dm³ (litres).  1 dm³ = 1000 cm³. The amount of solute can be measured in grams or moles. 2 units of concentration used in chemistry are … Read more

If a substance dissolves in a liquid, it is called a solute and the liquid is called the solvent. The resulting mixture is called a solution. Solute + Solvent = Solution Solute Solid which dissolves Solvent Liquid which does the dissolving Solution Solute + solvent Saturated solution A solution which will dissolve no more solute. … Read more

pH scale is a measure of acidity and alkalinity. Practically, it is numbered between 0 and 14.  Neutral substance has pH of 7. A solution of pH less than 7 is acidic The lower the pH, the more acidic the solution or the higher the concentration of H+ ions in the solution. A solution of … Read more

Strong Acids and Weak Acids Acids are chemical substances that ionize/dissociate in the presence of water to produce hydrogen ions (or hydroxonium ions). Acids can be classified into 2 categories: Strong acids Weak acids The strength of an acid depends on the degree of ionization/dissociation of the acid. Strong Acids Strong acids are acids that … Read more