Chemical Equation by Sigma Stock is a free Android application that provides a comprehensive set of tools for chemistry enthusiasts. The app offers over 13,000 chemical equations, including over 7,000 balanced equations, making it an excellent tool for students, teachers, and researchers.

The app also includes a periodic table, solubility rules table, and activity of metals table, which provide users with quick access to essential information. Additionally, there's a molecular weight calculator that allows users to calculate the molecular weight of any chemical compound. The balance chemical equation feature is another useful tool that helps users balance chemical equations effortlessly.

Overall, Chemical Equation is an excellent resource for anyone interested in chemistry. The app's user-friendly interface and the wealth of information it provides make it a must-have for chemistry enthusiasts.