Mabag, Viannery D., Mangune, Paolo D.
Chem 14.1, MAB1, Ms. Angelyn del Rosario
March 8, 2010
I. Abstract The experiment allowed students to explore different electrolytes and classify them into acids, bases and salts by using different indicators or by measuring the pH levels of each. The experiment also helped students classify different substances through their conductivity properties. The preparation of a 1 M stock solution from NaOH pellets diluted to a 0.1 M NaOH solution was also utilized in making the students understand the concept of titration. Using 0.1 M NaOH as a standard solution, the concentration of an unknown acid was calculated from the endpoint of an acid-base titration.
II. Keywords: acid, base, salt, pH, electrolytes, conductivity, titration
III. Introduction The experiment made the students classify substances as acids, bases, and salts using different indicators; identify pH; classify electrolytes as weak or strong based on conductivity; prepare 1 M NaOH from NaOH pellets; prepare 0.1 M NaOH from 1 M NaOH; determine endpoint of an acid-base titration; and calculate the concentration of an unknown acid solution based from titration data. Electrolytes are substances that dissociate into ions when dissolved in water. They are classifiable into acids, bases and salts using different indicators. An acid releases hydrogen ions, donates protons and accepts electron pairs. It is usually sour in taste and reacts vigorously with most metals. It also changes blue litmus paper to red. Moreover, it has a pH less than 7 and can be used to neutralize bases. A base, on the other hand, releases hydroxyl ions, accepts protons and donates electron pairs. It usually has a bitter taste and is nonreactive to metals. It has a pH more than 7 and changes red litmus paper to blue and can be used to neutralize acids. Salts result from the neutralization of an acid with a base. There are different indicators used to
References: Chang, R. (1998). Chemistry 6th ed. USA: McGraw-Hill Brown, T., et. al. (2003). Chemistry the central science 9th ed. Phils: PESA Ltd. Brown, T. Chemistry: The Central Science, Eight Edition. Prentice-Hall, Inc., 2002. I hereby certify that I have given substantial contribution to this report. VIANNERY D. MABAG PAOLO D. MANGUNE