Microfluidics for Personalized Reactions to Demonstrate Stoichiometry

Stoichiometry, the ideal gas law, and the concept of limiting reagent are challenging principles for students to conceptualize in introductory chemistry. These topics are fundamental to successfully mastering other chemistry content. Therefore, a handheld microfluidic device was designed as a new tool to visualize these principles. Using food-grade baking soda, vinegar, and carbonated water as reagents, the students were engaged in a hands-on learning experience. The baking soda and vinegar were the source of sodium bicarbonate and acetic acid which were combined in a 1:1 mol ratio to form carbon dioxide gas which was then quantified using the device, thereby illustrating the ideal gas law. Experiments were devised to support learning outcomes that involved using the ideal gas law to interconvert moles and volume, balancing chemical equations, quantifying the amount of product generated from a known amount of reactant, conveying measurement uncertainty, and postulating sources of experimental error. The microfluidic device is a fast and cost-effective tool to teach stoichiometry. Moreover, the use of food-grade reagents makes the activity accessible as well as safe enough to be conducted outside of a traditional laboratory setting.