======Acid/Base Calorimetry======


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**Alternative titles:** Heat of Neutralisation Calorimetry, Coffee-Cup Calorimeter
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====Summary====                   
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====Procedure====  
  -Assemble a coffee-cup calorimeter (polystyrene cup with lid), magnetic stirrer, stir bar, and calibrated thermometer or probe.
  -Measure 50.0 mL of ~1.0 M HCl and 50.0 mL of ~1.0 M NaOH in separate cylinders.
  -Place the stir bar and the acid into the cup; insert probe through the lid; stir gently and record a stable initial temperature (≈2–3 min).
  -Quickly add the base all at once, replace the lid, and stir continuously while recording temperature every 5–10 s.
  -Identify the maximum temperature; take ΔT = Tmax − Tinitial.
  -Estimate solution mass m by volume×density (≈100 g if 100 mL total); use c ≈ 4.18 J g⁻¹ K⁻¹; compute q = m c ΔT.
  -Determine limiting moles n (e.g., n = 0.0500 mol if 50.0 mL of 1.00 M); calculate ΔHneut = −q/n (report in kJ mol⁻¹; include sign).



====Links==== 
Acid Base Neutralization Calorimetry Lab - 100patoms: 
{{youtube>ZGTPBw5mTH0?}}\\

CHEM 111 Exp#12 - Calorimetry: Enthalpy of Neutralization Reactions - Dr. Carolynn Arpin: 
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📄 Understanding Enthalpy of Neutralisation - Catalyst: [[https://www.catalystchemistry.com.au/resources/mod6-acid-bases/iq1/5-enthalpy-of-neutralisation]]\\


====Variations====
  *Account for calorimeter heat capacity by determining a calorimeter constant from a hot–cold water calibration.
  *Repeat with weak acids or weak bases at the same formal concentration to compare enthalpies and heat loss effects.
  *Vary initial concentrations or volumes while keeping n the same.



====Safety Precautions====
  *Wear splash goggles, lab coat, and appropriate gloves.
  *HCl and NaOH are corrosive; avoid skin/eye contact and clean spills with plenty of water.
  *Do not seal the cup; gases and heat must vent.
  *Label acids and bases clearly; use separate, clean glassware for each.
  *Neutralise waste before disposal according to local rules; wash hands after the experiment.




====Questions to Consider====
  *Why is ΔHneut negative for strong acid–base reactions? (The reaction is exothermic; the solution gains heat that came from chemical potential energy.)
  *Why are values for strong acid–strong base near −57 kJ/mol? (They all essentially form 1 mol of water from H⁺ and OH⁻, with similar ionic solutions and minimal side processes.)
  *What assumptions were made in q = m c ΔT? (Density ≈ 1 g mL⁻¹, c ≈ water, negligible calorimeter heat capacity and heat loss.)
  *How would including a calorimeter constant change ΔH? (It increases q to account for heat absorbed by the cup, making ΔH more negative in magnitude.)
  *If acid and base are not equimolar, which n should be used? (Use moles of the limiting reactant, equal to moles of water formed.)