Calcium Carbonate Content In Toothpaste

2190 Words9 Pages
Synopsis This experiment is the determination of Calcium Carbonate (CaCO3) content in toothpaste with the use of back titration while demonstrating quantitative transfer of solids and liquids. A accurately weighed quantity of toothpaste was dissolved in excess volumes of HCl. This solution is then titrated with NaOH to find the volume of the excess HCl. The volume of HCl reacted, which is found by substracting the volume of given HCl with the volume of excess HCl reacted, can be further manipulated with mole fractions to find the mass of CaCO3 and thus the CaCO3 content in toothpastes. Results show that an average of 22.5% CaCO3 is found in toothpaste. Methyl Orange is noted to not be a suitable indicator for this experiment as the pH…show more content…
By measuring the volume of titrant used in a complete reaction, the quantity and hence the concentration of analyte used can be derived. However, certain chemical properties such as solubility in water and volatility makes standard titration undesirable for the substance. In this case, back titration is preferred. Toothpaste is made up of approximately 20% of Calcium Carbonate. When intermixed with an emulsifying agent, flavouring and water, it plays the role of an abrasive, to promote oral hygiene by removing dental plague and food from teeth. Calcium carbonate (CaCO3) is a chemical compound which comprises of one calcium atom bonded to one carbon atom and three oxygen atoms. It is available in natural forms such as chalk, limestone or the shells of snails and is obtained by mining or quarrying for industrial purposes. Regardless of acid strength,it causes a reaction with acids to produce carbon dioxide. This property makes up a simple and common way to identify Calcium…show more content…
In direct titrations, the number of moles of acid can be easily derived by simply manipulating with the values of acid and base given in the experiment. In back titration, excessive volumes of acid are always added. Of which, only a certain quantity would be neutralised. The number of moles of acid is eventually derived from titrating this excess acid with a strong base and using mole fractions to calculate. The quantity of acid neutralised is obtained by subtracting the moles of acid given at the start of the experiment, with the moles of acid titrated. Back titration is used for this experiment as Calcium Carbonate is volatile and is an insoluble salt. Therefore they cannot fully dilute with water. As it’s chemical and physical properties are non ideal for a Direct titration, Direct titration cannot be used to determine the Calcium Carbonate content in toothpaste. In Back titration, excess volumes of HCl acids are added to allow for titration with NaOH. Eventually, the moles of CaCO3 can be found via stoichiometric property of the two reactants, and the mass of CaCO3 can be determined.Thus, determining the CaCO3 content in

More about Calcium Carbonate Content In Toothpaste

Open Document