In this paper, we present the concept of Problem-Based Learning as a tool of integrating the basic knowledge previously acquired in a chemistry lesson to the mathematical modeling of pH-metrics. In like manner, we consider how to use this technique to bring the knowledge acquired in a calculus lesson into teaching electricity in a chemistry class. It involves some level of brain storming. Here active learning takes place and knowledge gained by students either way through a collaborative learning situation becomes personalized within the group. This underscores the need for the integration of the curricular of some basic concepts in mathematics and the sciences in general from the school level, thus it makes it easier for students in the tertiary educational level to learn higher and applicable concepts. Problem-based learning method then becomes an enviable tool which can be used in teaching both Mathematics and Chemistry at the Secondary and tertiary levels.