TITRATION OF A WEAK ACID WITH A STRONG BASE - From the experiment I have calculated that the molar enthalpy of neutralization for sodium hydroxide wiht sulphuric acid is -(54 3.2 kJ/mol).

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LAB #7:TITRATION OF A WEAK ACID WITH A STRONG BASE

Submitted by Tim Kwok

Chemistry 20 IB

Presented to Ms. Gierach

December 11, 2009

Design

Problem: Refer to teacher sheet.

Prediction:

Materials:

  • 10mL pipette
  • a burette
  • 150mL beakers
  • pH meter
  • a retort stand
  • sodium hydroxide acid solution
  • weak acid solution

Procedure: Refer to teacher sheet.

Variables:

Data Collection and Processing

Quantitative Data:

Pipette (mL) ±0.04mL  :

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Qualitative Data:

  • Beaker was warm after mixing the acid and base.

Processing:

        2 NaOH(aq)      +      H2SO4(aq)      =      2 H2O(l) + Na2SO4(aq)

c:        1.0mol/L        1.0mol/L

v:        50.0±0.2mL        30.0±0.2mL        80.0±0.4mL

T:        22.39±0.2°C        23.79±0.2°C        31.09±0.2°C

Temperature of Reactants: [(22.39±0.2°C)+( 23.79±0.2°C)]/2 = 23.09±0.2°C

Limiting Reagent: sodium hydroxide

Excess Reagent: sulphuric acid

Molar Enthalpy of neutralization for sodium hydroxide with sulphuric acid:

nΔrHm, NaOH = mcΔt

Δt = (31.09±0.2°C)-( 23.09±0.2°C) = 8.00±0.4°C

(0.050L ± 0.0002L NaOH(aq)) * 1mol NaOH(aq) * ΔrHm, NaOH = (0.080 ± 0.0004kg H2O(l)) * 4.19 kJ * (8.00± 0.4°C)

         1L NaOH(aq)           kg * °C

(0.050L ± 0.4% NaOH(aq)) ...

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