*Uncertainty Calculation for Rate of reaction, Enthalpy Change and Ideal Gas Equation.*

*Uncertainty Calculation for RMM using Ideal Gas Equation.*

*Ideal gas law equation, PV = nRT*

*Notes for Ideal Gas Equation.*

*V - volume in*

*m*^{3}

*n - number of moles*

*T - absolute temperature.(Kelvin)*

*R = gas constant,*

*8.314 J K*^{-1}mol^{-1}

*Calculate the RMM of a gas, given*

*M1, mass empty flask, = (25.385*

*±0.001)g*

*M2, mass flask filled with gas, = (26.017*

*±0.001)*

*g*

*M3, mass flask with water, = (231.985*

*±0.001)*

*g*

*Temperature = 32.0C = (273.0 +32.0) = (305.0*

*±0.1)K*

*Atmospheric pressure = 101,000 N*

*m*^{-2}

*/Pa*

*PV = nRT, n = mass/ RMM*

*PV = RT x mass/RMM*

*RMM = RT x mass / PV*

*Mass of gas = (M2 - M1) = (26.017 - 25.385)g = 0.632g*

*Vol of gas = Vol of flask = Vol of water = Mass of water = (231.985 - 25.385) = 206.6*

*x10*^{-6 }m3

*RMM = RT x mass / PV*

*RMM = 8.314 x 305.0 x 0.632 / 101,000 x*

*206.6*

*x10*^{-6}

*RMM (expt value) = 76.80 RMM (actual value) = 80.00*

*Percentage Error*

*= RMM (actual) - RMM (expt) /RMM (actual) x100%*

*= (80.00 - 76.80)/80.00 x 100%*

*= 3.20/80 x 100% = 4% (Error)*

*Percentage Uncertainty due random error ( Temp, Mass and Vol )*

*% Uncertainty Temp = (0.1/305.0 x 100)% = 0.0327% = 0.33%*

*% Uncertainty Mass gas = (0.002/0.632 x 100)% = 0.32%*

*% Uncertainty Vol = (0.002/206.6 ) x 100% = 0.000968% = 0.001%*

*Total % Uncertainty due to random error = ( 0.33 + 0.32 + 0.001 )% = 0.651% = 0.65%*

*Conclusion:**4% error is more than the total error due to all random error (T, Vol and Mass)**Systematic error have to account for the 3.35% difference which might be due to experimental procedure.**RMM = (76.8**± 0.65%) in percentage uncertainty**RMM = (**76.8 ± 0.5) in absolute uncertainty, max/min range is ( 76.3----77.3)*

**..........................................................................................................................................................**

*Simple Experimental setup*

*Determination of (RMM) of a gas ( CO2 or butane ) using ideal gas equation.*

*Steps to follow*

*1. Weigh a dry 100ml volumetric flask with stopper to 0.001g*

*2. Remove stopper*

*3. Fill it with CO2/butane gas with glass delivery tube, stopper it and reweigh*

*4. Repeat step 2 and 3 until mass of flask is constant*

*5. Fill the flask with water, insert a stopper, and reweigh it.*

*Click Here for IA on DCP and CE*

*Detail Experimental Setup*

*Click Here to view detail procedure setup.**Source from Chemistry SLSS website*

*Click HERE for more sample ideal gas calculation*

*Click HERE for more info on ideal gas equation***...........................................................................................................................................................**

*Uncertainty Calculation on Rate of reaction*

**IB Chemistry, IB Biology on Uncertainty calculation, error analysis and standard deviation on rate of reaction**

*Conclusion:**3 ways to calculate uncertainty for rate of reaction**1st method - using % percentage uncertainty method( most common)**2nd method - using Max/Min method**3rd method - using standard deviation method*

*.........................................................................................................................................*

*Uncertainty Calculation on Enthalpy Change*

*(Displacement Reaction)*

*Conclusion:**2 ways to calculate Uncertainty for Enthalpy Change (*ΔQ*)***1st method - using % percentage uncertainty method****2nd method - using Max/Min method**

*Thanks to all pictures and souces used for the above post*