This is an excellent opening activity to introduce the calculations for determining concentration of a solution. Students do a micro-titration of six NaOH solutions of increasing concentration with 1.0 M HCl. Phenolphthalein is used as an indicator. They then create a graph of drops of acid to NaOH concentration. They write an equation for the line, determine the slope, and write a formula for determining concentration or molarity. Students then determine the molarity of an unknown solution of NaOH.
This is a microchemistry lab, so once you set it up, all you have to do is top up the solutions and you are ready to go, year after year. A classroom set of table or station instructions greatly reduces paper usage and make these labs much easier to grade.
Inquiry labs are an excellent way to get students to think about how we know what we know in chemistry and I find them to be far more successful in a topic by using them. In addition, the change from hot pink for phenolphthalein to colorless is a breathtaking moment for students.
• Safe and simple to set up.
• Hands on experience
• Cooperative Learning
• Teacher instructions and set up
• Reinforcement of difficult concepts
• Lab Book Data Tables
• Student handouts with a key
chemistry, experiment, lab, laboratory, STEM, titration, acid, base, molarity, molality, normality, concentration, mole, moles, liters, neutralization, graph, linear, linear equation, constant,