Title : Determination of the relative molecular mass of amidosulpuric acid Data Collection
* Qualitative Data
1. Before the experiment :
a) The amidosulphuric acid is in powder crystal form .
b) The colour of sodium hydroxide is colourless .
c) The colour of distilled water after being dissolved with amidosulphuric acid is colourless .
2. During the experiment : After two drops of methyl red is being added to the solution of amidosulphuric acid , the solution changes from colourless to pale red
3. After the experiment : After the solution of amidoosulphuric acid that is being added with methyl red is titrated with certain volume of sodium hydroxide , the colour changes from pale red to orange .
* Quantitative Data
Mass of amidosulphuric acid = 2.4024 g ± 0.0001 g
| Trial| First | Second|
Initial volume of sodium hydroxide ,cm³ ± 0.05 cm³| 0| 24.1| 0| Final volume of sodium hydroxide , cm³ ± 0.05 cm³| 24.1| 48.6| 24.4| Volume of sodium hydroxide titrated , cm³ ± 0.10 cm³| 24.1| 24.5| 24.4| Table 1 : The intial volume and final volume of sodium hydroxide titrated
* Equation for the reaction = H₃NO₃S + NaOH -> Na₃NO₃S + H₂O * Average volume of sodium hydroxide titrated = 24.5 cm3+24.4 cm32 = 24.5 cm³
* Number of mole = Molarity x Volume
Number of mole of H₃NO₃S for 25 cm³ of NaOH
= 0.10 moldm-3 x 24.5 cm3 x 10 -3
Number of mole of H₃NO₃S for 250 cm3 of NaOH
= 0.002445 25 x 250 cm³
= 0.02445 mol
* Relative Molecular Mass of H₃NO₃S = MassMole
= 2.4024 g ± 0.0001g 0.02445 mol = 98.24
* Uncertainty for volume of amidosulphuric acid in pipette = ±0.05cm³
So , percentage error for volume amidosulphuric acid in pipette...