实验3缓冲溶液的配制与pH值的测定一实验目的72

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,*,实验3 缓冲溶液的配制与pH值的测定,一、实验目的,(1)了解缓冲溶液的配制原理及缓冲溶液的性质；,(2)掌握溶液配制的根本实验方法，学习pH计的使用方法,二、实验原理,(1)根本概念：在一定程度上能抵抗外加少量酸、碱或稀释，而保持溶液pH值根本不变的作用称为缓冲作用。具有缓冲作用的溶液称为缓冲溶液。,(2)缓冲溶液组成及计算公式：缓冲溶液一般是由共轭酸碱对组成的，例如弱酸和弱酸盐，或弱碱和弱碱盐。,如果缓冲溶液由弱酸和弱酸盐(例如HAc-NaAc)组成，那么,(3)缓冲溶液性质：,a.抗酸/碱,抗稀释作用:因为缓冲溶液中具有抗酸成分和抗碱成分，所以参加少量强酸或强碱，其pH值根本上是不变的。稀释缓冲溶液时，酸和碱的浓度比值不改变，适当稀释不影响其pH值。,b.缓冲容量:,缓冲容量是衡量缓冲溶液缓冲能力大小的尺度。缓冲容量的大小与缓冲组分浓度和缓冲组分的比值有关。缓冲组分浓度越大，缓冲容量越大；缓冲组分比值为 时，缓冲容量最大,。,三、,实验仪器与试剂,仪器：,pHS3C酸度计，试管，量筒(100mL，10mL)，烧杯(100mL，50mL)，吸量管(10mL)等,。,试剂：,HAc(0.1molL,-1,1molL,-1,)，NaAc(0.1molL,-1,1molL,-1,),NaH,2,PO,4,(0.1 molL,-1,)，Na,2,HPO,4,(0.1 molL,-1,),NH,3,H,2,O(0.1 molL,-1,)，NH,4,Cl(0.1 molL,-1,)，,HCl(0.1 molL,-1,)，NaOH(0.1 molL-1,1 molL,-1,)，,pH=4的HCl，pH10的NaOH，,pH=4.00标准缓冲溶液，pH=9.18标准缓冲溶液,甲基红溶液,广泛pH试纸,精密pH试纸,吸水纸等。,四、实验步骤,缓冲溶液的配制与pH值的测定,依表1进行实验。并将实验数据记录(溶液留作后面实验用)。,缓冲溶液的性质,根据表2进行实验，并将实验结果记录在表中。,表1 缓冲溶液的配制与pH值的测定,实验号,理论pH值,各组分的体积/mL,(总体积50mL),精密pH试纸,测定pH值,PH计,测定pH值,甲,4.0,0.1molL,-1,HAc,0.1molL,-1,NaAc,乙,7.0,0.1molL,-1,NaH,2,PO,4,0.1molL,-1,Na,2,HPO,4,丙,10.0,0.1molL,-1,NH,3,H,2,O,0.1molL,-1,NH,4,Cl,实验号,溶液类别,pH值,加5滴HCl后pH值,加5滴NaOH 后pH值,加10mL水后pH值,1,蒸馏水,2,pH=4的HCl溶液,3,pH=10的NaOH溶液,4,pH=4.0的缓冲溶液,5,pH=7.0的缓冲溶液,6,PH=10.0的缓冲溶液,表2 缓冲溶液的性质,缓冲溶液的缓冲容量,缓冲容量与缓冲组分浓度的关系,HAc和NaAc各3mL,HAc和NaAc各3mL,浓度均为0.1mol,L,-1,精密pH试纸,两滴甲基红溶液,滴加NaOH至黄色,？,？,甲基红在pH6.3时呈黄色,记录两试管的NaOH滴数,浓度均为1mol,L,-1,NaH,2,PO,4,和,Na,2,HPO,4,各,10mL,?,?,1.8mL0.1 mol,L,-1,NaOH,精密,pH,试纸,?,说明哪一试管中缓冲溶液的缓冲容量大。,缓冲容量与缓冲组分比值的关系,2mL NaH,2,PO,4,和,18mL,Na,2,HPO,4,五、本卷须知,实验室平安问题。,缓冲溶液的配制要注意精确度。,了解pH计的正确使用方法，注意电极的保护。,六、思考题,(1)为什么缓冲溶液具有缓冲作用？,(2)NaHCO3溶液是否具有缓冲作用，为什么？,(3)用pH计测定溶液pH值时，已经标定的仪器，“定位调节是否改变位置，为什么？,x-A1D5G8KbNeQiTlWo#r%v(y+B3E6H9LcOfRjUmYp!s&w)z0C4F7JaMdPhSkVnZq$u*x-A2D5G8KbNfQiTlXo#r%v(y0B3E6I9LcOgRjVmYp!t&w)z1C4G7JaMePhSkWnZq$u*x+A2D5H8KbNfQiUlXo#s%v(y0B3B3F6I9LdOgRjVmYq!t&w-z1C4G7JbMePhTkWnZr$u(x+A2E5H8KcNfRiUlXp#s%v)y0C3F6IaLdOgSjVnYq!t*w-z1D4G7JbMeQhTkWoZr$u(x+B2E5H9KcNfRiUmXp#s&v)y0C3F7IaLdPgSjVnYq$t*w-A1D4G8JbNeQhTlWoZr%u(y+B2E6H9KcOfRiUmXp!s&v)z0C3F7IaMdPgSkVnYq$t*x-A1D5G8JbNeQiTlWo#r%u(y+B3E6H9LcOfRjUmYp!s&w)z0C4F7JaMdPhSkVnZq$u*x-A2D5G8KbNeQiTlXo#r%v(y+B3E6I9LcOgRjUmYp!t&w)z1C4F7JaMePhSkWnZq$u*x+A2D5H8KbNfQiUlXo#s%v(y0B3F6I9LdOgRjVmYp!t&w-z1C4G7JaMePhTkWnZr$u*x+A2E5H8KcNfQiUlXp#s%v)y0B3F6IaLdOgSjVmYq!t*w-z1D4G7JbMeQhTkWoZr$u(x+A2E5H9KcNfRiUlXp#s&v)y0C3F6IaLdPgSjVnYq!t*w-A1D4G8JbMeQhTlWoZr%u(x+B2E6H9KcOfRiUmXp!s&v)z0C3F7IaMdPgSkVnYq$t*w-A1D5G8JbNeQhTlWo#r%u(y+B2E6H9LcOfRjUmXp!s&w)z0C4F7IaMdPhSkVnZq$t*x-A2D5G8KbNeQiTlXo#r%v(y+B3E6H9LcOgRjUmYp!s&w)z1C4F7JaMdPhSkWnZq$u*x-A2D5H8KbNfQiTlXo#s%v(y0B3E6I9LdOgRjVmYp!t&w-z1C4G7JaMePhTkWnZr$u*x+A2D5H8KcNfQiUlXo#s%v)y0B3F6I9LdOgSjVmYq!t&w-z1D4G7JbMePhTkWoZr$u(x+A2E5H9KcNfRiUlXp#s&v)y0C3F6IaLdOgSjVnYq!t*w-z1D4G8JbMeQhTkWoZr%u(x+B2E5H9KcOfRiUmXp#s&v)z0C3F7IaLdPgSkVnYq$t*w-A1D5G8JbNeQhTlWoZr%u(y+B2E6H9KcOfRjUmXp!s&v)z0C4F7IaMdPgSkVnZq$t*x-A1D5G8G8KbNeQiTlWo#r%v(y+B3E6H9LcOgRjUmYp!s&w)z1C4F7JaMdPhSkWnZq$u*x-A2D5G8KbNfQiTlXo#r%v(y0B3E6I9LcOgRjVmYp!t&w)z1C4G7JaMePhSkWnZr$u*x+A2D5H8KcNfQiUlXo#s%v)y0B3F6I9LdOgSjVmYq!t&w-z1C4G7JbMePhTkWnZr$u(x+A2E5H8KcNfRiUlXp#s%v)y0C3F6IaLdOgSjVnYq!t*w-z1D4G8JbMeQhTkWoZr%u(x+B2E5H9KcNfRiUmXp#s&v)y0C3F7IaLdPgSjVnYq$t*w-A1D4G8JbNeQhTlWoZr%u(y+B2E6H9KcOfRjUmXp!s&v)z0C4F7IaMdPgSkVnYq$t*x-A1D5G8JbNeQiTlWo#r%u(y+B3E6H9LcOfRjUmYp!s&w)z0C4F7JaMdPhSkVnZq$u*x-A2D5G8KbNfQiTlXo#r%v(y0B3E6I9LcOgRjUmYp!t&w)z1C4F7JaMePhSkWnZq$u*x+A2D5H8KbNfQiUlXo#s%v(y0B3F6I9LdOgRjVmYq!t&w-z1C4G7JbMePhTkWnZr$u*x+A2E5H8KcNfQiUlXp#s%v)y0B3F6IaLdOgSjVmYq!t*w-z1D4G7JbMeQhTkWoZr$u(x+B2E5H9KcNfRiUmXp#s&v)y0C3F6IaLdPgSjVnYq!t*w-A1D4G8JbMeQhTlWoZr%u(x+B2E6H9KcOfRiUmXp!s&v)z0C3F7IaMdPgSkVnYq$t*x-A1D5G8JbNeQiTlWo#r%u(y+B2E6H9LcOfRjUmXp!s&w)z0C4F7IaMdPhSkVnZq$t*x-A2D5G8KbNeQiTlXo#r%v(y+B3E6I9LcOgRjUmYp!t&w)z1C4F7JaMdPhSkWnZq$u*x-A2D5H8KbNfQiTlXo#s%v(y0B3E6I9LdLdOgRjVmYp!t&w-z1C4G7JaMePhTkWnZr$u*x+A2E5H8KcNfQiUlXp#s%v)y0B3F6IaLdOgSjVmYq!t&w-z1D4G7JbMePhTkWoZr$u(x+A2E5H9KcNfRiUlXp#s&v)y0C3F6IaLdPgSjVnYq!t*w-A1D4G8JbMeQhTlWoZr%u(x+B2E5H9KcOfRiUmXp#s&v)z0C3F7IaLdPgSkVnYq$t*w-A1D5G8JbNeQhTlWo#r%u(y+B2E6H9LcOfRjUmXp!s&w)z0C4F7IaMdPhSkVnZq$t*x-A1D5G8KbNeQiTlWo#r%v(y+B3E6H9LcOgRjUmYp!s&w)z1C4F7JaMdPhSkWnZq$u*x-A2D5H8KbNfQiTlXo#s%v(y0B3E6I9LcOgRjVmYp!t&w)z1C4G7JaMePhSkWnZr$u*x+A2D5H8KcNfQiUlXo#s%v)y0B3F6I9LdOgSjVmYq!t&w-z1D4G7JbMePhTkWnZoZr$u(x+A2E5H9KcNfRiUlXp#s%v)y0C3F6IaLdOgSjVnYq!t*w-z1D4G8JbMeQhTkWoZr%u(x+B2E5H9KcOfRiUmXp#s&v)z0C3F7IaLdPgSkVnYq$t*w-A1D4G8JbNeQhTlWoZr%u(y+B2E6H9KcOfRjUmXp!s&v)z0C4F7IaMdPgSkVnZq$t*x-A1D5G8KbNeQiTlWo#r%v(y+B3E6H9LcOgRjUmYp!s&w)z0C4F7JaMdPhSkVnZq$u*x-A2D5G8KbNfQiTlXo#r%v(y0B3E6I9LcOgRjVmYp!t&w)z1C4G7JaMePhSkWnZr$u*x+A2D5H8KbNfQiUlXo#s%v(y0B3F6I9LdOgRjVmYq!t&w-z1C4G7JbMePhTkWnZr$u(x+A2E5H8KcNfRiUlXp#s%v)y0C3F6IaLdOgSjVmYq!t*w-z1D4G7JbMeQhTkWoZr$u(x+B2E5H9KcNfRiUmXp#s&v)y0C3F7IaLdPgSjVnYq$t*w-A1D4G8JbNeQhTlWoZr%u(y+B2E6H9KcOfRiUmXp!s&v)z0C3F7IaMdPgSkVnYq$t*x-A1D5G8JbNeQiTlWo#r%u(y+B3E6H9LcOfRjUmYp!s&w)z0C4F7JaMdPhSkVnZq$t*x-A2D5G8KbNeQiTlXo#r%v(y+B3E6E6I9LcOgRjUmYp!t&w)z1C4F7JaMePhSkWnZq$u*x+A2D5H8KbNfQiUlXo#s%v(y0B3F6I9LdOgRj