最大气泡法测表面张力实验数据及处理

五、实验数据记录与处理室温：24.3℃大气压：100.73Pa1、乙醇水溶液的折光率利用文献数据作n~c工作曲线，依据实验测定数据，计算样品的浓度c。（1）将25℃时乙醇-水溶液的浓度与折光率关系表（表一），绘制成溶液浓度与折光率的工作曲线（图一）。25℃恒温水浴下测得水的折射率为：1.3322/1.3323/1.3323求得平均值为：1.332266667利用水的折射率校正：c/(mol/L)00.911.702.623.554.105.218.5812.0013.5917.17n1.33251.33581.3381.3411.3441.34621.34921.35781.36211.36391.3696校正后n1.33231.33561.33781.34081.34381.34601.34901.35761.36191.36371.3694表一25℃时乙醇-水溶液的浓度与折光率关系表-20246810121416181.3301.3351.3401.3451.3501.3551.3601.3651.370(c,n)n~c拟合直线nc/(mol/L)Equationy=a+b*xWeightNoWeightingResidualSumofSquares4.77129E-5Pearson'sr0.98459Adj.R-Square0.96601ValueStandardErrornIntercept1.335270.00106nSlope0.002151.27518E-4图一溶液浓度与折光率的工作曲线（2）实验配制的乙醇溶液折光率数据如表二所示。乙醇溶液配制浓度5%10%15%20%25%30%35%40%乙醇质量/g2.505.007.5010.0012.5015.0017.5020.00水的质量/g47.5045.0042.5040.0037.5035.0032.5030.00乙醇称重/g2.53505.06307.629010.148012.798015.729017.591520.1945水称重/g47.976044.982242.883340.921137.486135.425732.565830.0288折光率11.33551.33861.34201.34551.34881.35161.35381.355521.33561.33861.34211.34551.34901.35161.35401.355831.33551.33881.34221.34551.34881.35181.35411.3559平均1.33551.33871.34211.34551.34891.35171.35401.3557表二乙醇的折光率（3）将校正后的乙醇的折光率代入拟合直线方程中，得到各乙醇溶液的真实浓度。如表三所示。乙醇浓度5%10%15%20%25%30%35%40%折光率n1.33551.33871.34211.34551.34891.35171.35401.3557校正后n1.33531.33841.34191.34531.34861.35141.35371.3555浓度c(mol/L)0.01201.46703.06134.64016.20357.50378.57179.3921表三乙醇溶液的浓度2、待测液体的表面张力将实验测得的水和乙醇溶液的最大△Pmax值代入公式：γ测=（△Pmax，测*γ水）/△Pmax，水（查阅附表，得γ水=0.07197N/m）求得各乙醇溶液的表面张力如表四所示。△Pmax,测(mmH2O)△Pmax,平均(mmH2O)γ/(N/m)蒸馏水160.661.460.860.91117.197E-02260.561.360.8360.661.360.9乙醇5%54.754.754.354.56676.447E-0210%40.340.340.540.36674.770E-0215%34.934.935.134.96674.132E-0220%31.331.331.331.30003.698E-0225%29.229.229.229.20003.450E-0230%26.526.526.526.50003.131E-0235%26.126.226.126.13333.088E-0240%24.524.524.524.50002.895E-02表四待测样品的表面张力测定3、作γ~c曲线，求出各浓度下的斜率。（1）作γ~c拟合曲线。γ，c的相关数据如表五所示，拟合直线见图二。c0.01201.46703.06134.64016.20357.50378.57179.3921γ/(N/m)0.064470.047700.041320.036980.034500.031310.030880.02895表五γ，c的相关数据02468100.030.040.050.06(c,)~c拟合曲线γ/(N/m)c(mol/L)ModelPow2P2Equationy=a*(1+x)^bReducedChi-Sqr4.36787E-7Adj.R-Square0.99687ValueStandardErrorγ/(N/m)a0.065116.08759E-4γ/(N/m)b-0.334210.00651图二γ~c拟合曲线（2）用origin作出γ~c拟合曲线的斜率曲线，如图三所示。0510-0.02-0.010.00DerivativeY1DerivativeX1图三γ~c拟合曲线的斜率曲线（3）将各乙醇溶液浓度代入斜率曲线，求出待测样品的(∂γ/∂c)T，P数据。数据见表六。c/mol/L0.012031.467023.061314.640136.203477.503678.571699.39206斜率-0.0212-0.0065-0.0033-0.0022-0.0016-0.0013-0.0011-0.00091表六待测样品的(∂γ/∂c)T，P数据4、利用吉布斯吸附等温方程式，计算出各溶液的Γ。Gibbs公式：Γ=PTc,)(RTc-其中，R=8.314J/(mol*K),T=25.0+273.15=298.15K将表六中数据代入公式，求出各溶液的Γ如表七所示。c斜率Γc/Γ0.01203-0.021221.02983E-07116815.22621.46702-0.006543.87052E-06379024.32723.06131-0.003334.11251E-06744390.12014.64013-0.002184.08077E-061137072.9826.20347-0.001553.87902E-061599238.1297.50367-0.001263.81416E-061967316.7468.57169-0.001063.66545E-062338508.5859.39206-9.07E-043.43495E-062734265.081表七待测样品的Γ及c/Γ数据5、做c/Γ~c图，求出直线斜率，由斜率求出Γ∞，直线如图三所示。02468100.05.0x1051.0x1061.5x1062.0x1062.5x1063.0x106(c,c/Γ)c/Γ~c拟合直线c/Γc(mol/L)Equationy=a+b*xWeightNoWeightingResidualSumofSquares5.2061E11Pearson'sr0.99351Adj.R-Square0.91612ValueStandardErrorc/ΓIntercept348768.9980696418.87957c/ΓSlope201375.8023--图三c/Γ~c图根据公式：Kc1c直线斜率的倒数即为Γ∞所以Γ∞=4.9658*10-6mol/m26、计算乙醇分子的横截面积根据公式Am=1/Γ∞LL=6.023*1023mol-1求出乙醇分子内的横截面积为Am=3.3434*10-19m2