Rate of reaction: mass loss template

Conical flask of marble chips and dilute HCl with a cotton wool plug on a top-pan balance, and a stopwatch; plot mass lost against time. GCSE to A-level / AP / IB.

What the template shows

• Follow a reaction that gives off a gas by weighing it as it goes
• Top-pan balance
• Add the chips, plug the flask, start the clock and read the mass every 30 s (or tare and read the loss directly)
• Cotton wool plug
• Lets CO₂ out but keeps acid spray in
• Marble chips + dilute HCl
• CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂; mass lost = mass of CO₂ given off
• Rate = gradient of the mass-lost curve; a tangent at t = 0 gives the initial rate. Gas syringe: the other common method
• Reaction setup

Drawn with 10 shapes – every one editable in MolDraw.

Sources

• Atkins, de Paula & Keeler, Atkins' Physical Chemistry, 11th ed., OUP 2018 Textbook