分析化学北京大学003省公开课金奖全国赛课一等奖微课获奖PPT课件.pptx

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,第一章,分析化学概论,1.,基本概念:,滴定分析对反应要求、滴定方式、基准物质、标准溶液,2.滴定分析计算:,M,(,M,r,)、,m,、,n,、,c,、,V,、,w、,之间关系,滴定剂(,n,A,)与被测物(,n,B,)关系:,等物质量规则,、,换算因数法,1,1/32,2.1 误差基本概念:准确度(,T,、,E,a,、,E,r,),与精密度（偏差）、系统误差与随机误差;,2.2 随机误差分布,2.3,有限数据统计处理,:、,R,、,RR,、,d,i,、,Rd,i,、,s,、CV；,异常值检验（,Q,检验法）；,2.4,测定方法选择和测定准确度提升,2.5,有效数字,：定义、修约规则、运算规则,、,汇报结果。,第二章,误差与分析数据处理,x,x,d,Rd,2,2/32,第三章 酸碱平衡及酸碱滴定法,3.1 酸碱反应及其平衡常数,3.2 酸度对弱酸(碱)形体分布影响,3.3 酸碱溶液H,+,浓度计算,3.4 酸碱缓冲溶液,3.5 酸碱指示剂,3.6 酸碱滴定曲线和指示剂选择,3.7 终点误差(不要求),3.8 酸碱滴定法应用,3.9 非水溶剂中酸碱滴定(不要求),3,3/32,3.1,酸碱反应及其平衡常数,3.1.1,酸碱反应,(p53),酸 共轭碱 +质子,Proton donor Proton acceptor Proton,HAc,Ac,-,+H,+,NH,4,+,NH,3,+H,+,HCO,3,-,CO,3,2-,+H,+,H,6,Y,2+,H,5,Y,+,+H,+,通式,:HA A +H,+,共轭酸 碱 +质子,酸碱半反应,4,4/32,例:,HAc在水中离解反应,（,p53）,半反应1:,HAc,Ac,-,+H,+,半反应2:,H,+,+H,2,O,H,3,O,+,总反应:HAc+H,2,O,Ac,-,+H,3,O,+,简写为:HAc,Ac,-,+H,+,酸碱反应实质是质子转移,5,5/32,+,6,6/32,-,7,7/32,3.1.2,酸碱反应类型及平衡常数,（p55）,a.一元弱酸(碱)离解反应,HA +H,2,O,A,-,+H,3,O,+,A +H,2,O,HA,+OH,-,8,8/32,H,2,O+H,2,O,H,3,O,+,+OH,-,(25,C),共轭酸碱对,(HA-A),K,a,与,K,b,关系为,b.,水质子自递反应,（p55),9,9/32,R.Kellner,Analytical Chemistry,p94,p,K,w,，as a function of temperature,.,t,0,C,0,10,20,25,30,40,50,60,p,K,w,14.96,14.53,14.16,14.00,13.83,13.53,13.26,13.02,中性水pH =7.00,?,中性水pH=pOH,10,10/32,p,K,b1,=14.00,-,p,K,a3,p,K,b2,=14.00-,p,K,a2,p,K,b3,=14.00-,p,K,a1,c.多元酸碱离解反应,（p56）,H,3,A,H,2,A,-,HA,2-,A,3-,11,11/32,d.酸碱中和反应(滴定反应,),（p57）,K,t,滴定反应常数,H,+,+OH,-,H,2,O,H,+,+A,-,HA,OH,-,+HA,H,2,O,+A,-,12,12/32,3.1.3,活度与浓度,(p5758),Debye-H,ckel公式,:,。,。,13,13/32,0 0.1 0.2 0.3 0.4 0.5,I,/molL,-1,。,Debye-H,ckel公式,14,14/32,活度系数图,0.1 0.2 0.3 0.4 0.5,I,/molL,-1,1.0,0.5,1.,I,一定,电荷数高,2.,电荷数一定,I,3.0 0.1,0.1 0.5,两段,15,15/32,3.1.4,活度常数,K,a,、浓度常数 及混合常数,反应：HAc H,+,+Ac,-,查附录III.1,16,16/32,是否一元弱酸常数之间都符合上述关系？,17,17/32,K,a,:Thermodynamic Constant(只与,t,相关),:Concentration Constant(与,t,I,相关),:Mixed Constant (与,t,I,相关),1.本章用,K,a,处理平衡浓度之间关系；,2.离子强度较高时,用,I,=0.1,如第四章（络合滴定）,18,18/32,3.2.1,一元弱酸摩尔分数,(p61 62),3.2,酸度对弱酸(碱)形体分布影响,HA=H,+,+A,-,c,(HA)=HA+A,-,19,19/32,“,x,”将平衡浓度与分析浓度联络起来,20,20/32,例3.5,计算pH4.00和8.00时,x,(HAc)、,x,(Ac,-,),解:已知HAc,K,a,=1.7510,-5,pH=4.00时,pH=8.00时,x,(HAc)=5.710,-4,x,(Ac,-,)1.0,（p62）,21,21/32,HA H,+,+A,-,假设H,+,A,-,等离子不能穿透隔膜,HA分子可,自由经过隔膜.达平衡时,隔膜两边HA浓度,相等,但总药浓度不一样.,阿司匹林是一个弱酸(即乙酰水杨酸),p,K,a,=3.5.计算在血浆中总药剂量(HA+A),对胃中总药剂量比率,.,例,:药品吸收方式可表示为,pH=7.4 pH=1.0,血浆,隔膜,胃,H,+,+A,-,HA,22,22/32,23,23/32,pH,x,(HA),x,(A,-,),p,K,a,-2.0,0.99,0.01,*p,K,a,-1.3,0.95,0.05,p,K,a,-1.0,0.91,0.09,*p,K,a,0.50,0.50,p,K,a,+1.0,0.09,0.91,*p,K,a,+1.3,0.05,0.95,p,K,a,+2.0,0.01,0.99,以,x,对pH作图,得形体分布图,不一样pH下,x,(HA)与,x,(A,-,),24,24/32,HAc,x,-pH图,（p62）,p,K,a,4.76,HAc优势区域图,0 2 4 6 8 10 12 pH,1.0,0.5,0.0,4.76,Ac,-,HAc,x,3.46 6.06,p,K,a,1.3,pH,HAc,Ac,-,4.76,25,25/32,HF,x,-pH图,1.0,0.5,0.0,x,0 2 4 6 8 10 12 pH,3.17,HF,F,-,p,K,a,3.17,pH,HF,F,-,HF优势区域图,26,26/32,HCN,x,-pH图,0 2 4 6 8 10 12 pH,1.0,0.5,0.0,x,9.31,p,K,a,9.31,HCN,CN,-,HCN优势区域图,HCN,CN,-,pH,27,27/32,3.2.2 二元弱酸H,2,A摩尔分数,（6465）,28,28/32,H,2,CO,3,x,-pH图,1.0,0.5,0.0,0 2 4 6 8 10 12 pH,x,H,2,CO,3,HCO,3,-,CO,3,2,-,H,2,CO,3,HCO,3,-,CO,3,2,-,6.38,p,K,a1,10.25,p,K,a2,p,K,a,=3.87,pH,29,29/32,酒石酸(H,2,A),x,-pH图,(p66),H,2,A,HA,-,A,2,-,p,K,a1,p,K,a2,p,K,a,=1.33,pH,1.0,0.5,0.0,0 2 4 6 8 10 12 pH,x,H,2,A,HA,-,A,2,-,3.04 4.37,30,30/32,三元酸H,3,A摩尔分数,（p66）,分母由4项组成:,M,=H,+,3,+H,+,2,K,a1,+H,+,K,a1,K,a2,+,K,a1,K,a2,K,a3,x,3,=H,3,A/,c,=H,+,3,/,M,x,2,=H,2,A,-,/,c,=H,+,2,K,a1,/,M,x,1,=HA,2-,/,c,=H,+,K,a1,K,a2,/,M,x,0,=A,3-,/,c,=,K,a1,K,a2,K,a3,/,M,31,31/32,磷酸(H,3,A)型体分布图,(p67),H,3,PO,4,H,2,PO,4,-,HPO,4,2,-,PO,4,3,-,2.16,p,K,a,5.05,7.21,p,K,a,5.11,12.32,p,K,a1,p,K,a2,p,K,a3,1.0,0.5,0.0,0 2 4 6 8 10 12 pH,x,H,3,PO,4,H,2,PO,4,-,HPO,4,2,-,PO,4,3,-,32,32/32,