NaOH溶液的配制和标定

NaOH溶液的配制和标定 一、教学要求 1、学会NaOH标准溶液的配制与标定; 2、练习台天平的使用，掌握固体强碱的称量方法; 3、了解基准物质邻苯二甲酸氢钾(KHCHO)和草酸(HCO?HO)的性质及其应用; 8442242 4、熟悉电子天平的使用，掌握差减法称取基准物质的操作步骤; 5、学会用基准物质配制标准溶液的方法; 6、学会容量瓶和移液管的正确使用; 7、掌握强碱滴定弱酸的滴定过程，突跃范围及指示剂的选择原理。 二、预习内容 1、台天平的构造及应用; 2、电子天平的称量原理、操作过程及注意事项; 3、容量瓶和移液管的规格、使用; 4、滴定管的规格、洗涤、涂油、润洗等操作步骤; 5、固体NaOH的性质、NaOH溶液的储存注意事项; 6、基准物质的性质、常用基准物质的种类及应用。 三、基本操作 1、容量瓶的使用 (1)定义: 容量瓶是一种细颈梨形平底玻璃瓶，主要用于配制准确浓度的溶液或定量的稀释溶液。 (2)使用前检漏: 加水至标线附近，盖好瓶塞后，左手用食指按住塞子，其余手指拿住瓶颈标线以上部分，右手指尖托住瓶底，将瓶倒立2分钟，如不漏水，将瓶直立，转动瓶塞180?，再倒立2分钟，如不漏可使用。(使用中，玻璃塞不应放在桌面上，以免玷污，操作时可用一手的食指和中指夹瓶塞的扁头，当操作结束后随手将瓶盖盖上，也可用橡皮筋或细绳将瓶塞系在瓶颈上)。 (3)洗涤: 一般先用自来水洗，最后用蒸馏水水洗3次备用。 (4)定量稀释溶液: 用移液管移取一定体积的溶液于容量瓶中，加水至距标线约1cm处，等1,2分钟，intensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, multiple groups from a single radiation-belt open development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whole city and culture series supporting role, with natural landscapes and green for the background, according to the combined city, urban Group organization structure, set up a decentralized development patterns, building ... Three rivers: the Yangtze, jinsha River and minjiang rivers, cities in three rivers based on development along the Yangtze River, city on the River, River in the city. Multiple groups: the relatively compact area layout, each district consists of multiple groups, and the area has both integrated urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangdong characteristic tour area and Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze River belt. Dvn group in the upper reaches of the jinsha River along the river continues to the East to South stream groups, layout along the city's main commercial, business, administrative, cultural and creative research and development in science and education function of modern service and port equipment manufacturing, liquor, and other features and modern industry. 2.5-2 spatial planning figure 2.6 in Yibin city, Central City urban development vision vision 使附在瓶颈内壁的溶液流下后，再用滴管滴加水至弯液面下缘与标线相切，然后盖上瓶塞，左手用食指按住塞子，其余手指拿住瓶颈标线以上部分，右手指尖托住瓶底，将容量瓶倒转，使气泡上升到顶，使瓶振荡，正立后再次倒转进行振荡，如此反复15,20次以上，使瓶内溶液混合均匀。 (5)溶液的配制: 将准确称量的待溶固体置于小烧杯中，加水溶解，然后将溶液定量转入容量瓶中。定量转移溶液时，右手拿玻璃棒，左手拿烧杯，使烧杯嘴紧靠玻璃棒，玻璃棒的下端靠在瓶颈内壁上，使溶液沿玻璃棒和内壁流入容量瓶中，烧杯中溶液流完后，将烧杯沿玻璃棒向上提，并逐渐竖直烧杯，将玻璃棒放回烧杯，用洗瓶冲洗玻璃棒和烧杯壁数次，将洗液用如上方法定量转入容量瓶中，定量转移完成后就可以加蒸馏水稀释，当蒸馏水加至容量瓶鼓肚的四分之三处时，塞上塞子，用右手食指和中指夹住瓶塞，将瓶拿起，按同一方向轻轻摇转，使溶液初步混合均匀(注意不能倒转)，继续加蒸馏水至距标线约1cm处，等1,2分钟，使附在瓶颈内壁的溶液流下后，再用滴管滴加水至弯液面下缘与标线相切，然后盖上瓶塞，左手用食指按住塞子，其余手指拿住瓶颈标线以上部分，右手指尖托住瓶底，将容量瓶倒转，使气泡上升到顶，使瓶振荡，正立后再次倒转进行振荡，如此反复15,20次以上，使瓶内溶液混合均匀。 溶液的转移 容量瓶的拿法 2、移液管的使用 (1)定义 移液管是用于准确量取一定体积溶液的量出式玻璃量器。 (2)润洗: 使用前用吸水纸将尖端内外的水除去，然后用待吸液润洗三次:左手持洗耳球，右手拇指和中指拿住标线以上部分，将移液管管尖插入约溶液1,2cm，将待吸液吸至球部1/4处，移出，荡洗，弃去(切记从尖口放出,应保持上管口和食指干燥)。 anning figure 2.6 in Yibin city, Central City urban development vision vision2 spatial pl-ation function of modern service and port equipment manufacturing, liquor, and other features and modern industry. 2.5long the city's main commercial, business, administrative, cultural and creative research and development in science and educyout ar belt. Dvn group in the upper reaches of the jinsha River along the river continues to the East to South stream groups, laharacteristic tour area and Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze Rivedong cthe area has both integrated urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangiver, River in the city. Multiple groups: the relatively compact area layout, each district consists of multiple groups, and the R : the Yangtze, jinsha River and minjiang rivers, cities in three rivers based on development along the Yangtze River, city onthe combined city, urban Group organization structure, set up a decentralized development patterns, building ... Three riverse city and culture series supporting role, with natural landscapes and green for the background, according to belt open development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whol-m a single radiationtiple groups frointensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, mul2 (3)移液: 左手持洗耳球，右手拇指和中指拿住标线以上部分，将移液管管尖插入约溶液1,2cm，将待吸液吸至标线以上，迅速移去洗耳球，同时用右手食指堵住管口，左手改拿盛待吸液的容器。然后，将移液管往上提起，使之离开液面，并将原深入溶液部分沿容器内部轻转两圈，以除去管壁上的溶液。使容器倾斜30度，其内壁与移液管尖紧贴，同时右手食指微微松动，使液面缓慢下降，直到管内溶液的弯月面与标线相切，这时应立即用食指按紧管口，移开待吸液容器，左手改拿接受溶液的容器，并将接受容器倾斜，使内壁紧贴移液管尖，成30度左右，然后放松右手食指，使溶液自然顺壁流下，待液面下降到管尖后，等15秒左右，移出移液管。(除特别注明，管尖残留溶液不吹入接受容器中)。 用移液管吸取溶液 从移液管放出溶液 3、滴定管的使用: (1)定义: 滴定管是可准确测量滴定剂体积的玻璃量器。 (2)类别: 酸式滴定管:(特征—玻璃旋塞)用于盛放酸性溶液、中性溶液和氧化性溶液。 碱式滴定管:(特征—橡皮管+玻璃珠)用于盛放碱性和无氧化性溶液。 (3)滴定管的准备: a、用前检查:检查是否漏水，旋塞转动是否灵活;酸式管涂凡士林;碱式管更换胶皮管或玻璃球。 ervice and port equipment manufacturing, liquor, and other features and modern industry. 2.5rcial, business, administrative, cultural and creative research and development in science and education function of modern scommeupper reaches of the jinsha River along the river continues to the East to South stream groups, layout along the city's main d Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze River belt. Dvn group in therea aned urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangdong characteristic tour aultiple groups: the relatively compact area layout, each district consists of multiple groups, and the area has both integratity. Mr and minjiang rivers, cities in three rivers based on development along the Yangtze River, city on the River, River in the croup organization structure, set up a decentralized development patterns, building ... Three rivers: the Yangtze, jinsha Riverban Gy and culture series supporting role, with natural landscapes and green for the background, according to the combined city, uopen development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whole citbelt -tiple groups from a single radiationintensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, mulcity, Central City urban development vision vision 2 spatial planning figure 2.6 in Yibin-3 活塞涂凡士林 碱式滴定管赶去气泡的方法 b、洗涤:要求管壁湿润洁净，不挂水珠。 (4)溶液的装入: a、用待装液润洗2,3次，每次约10mL; b、装液至0.00刻度以上; c、排气泡; d、调节初读数为0.00，或近0的任一刻度，以减小体积误差。 (4)滴定操作: a、酸式滴定管:左手无名指和小指向手心弯曲，其余三指，拇指在前，食指、中指在后，轻扣旋塞，转动。 碱式滴定管:左手无名指及小指夹住尖嘴管，拇指与食指捏乳胶管，使玻璃球向手心移动，停止时，先松拇指和食指。 b、滴加方法:逐滴连续滴加;加一滴;使液滴悬而未落，即加半滴于锥形瓶壁(或用蒸馏水冲下或用溶液涮下)。 、锥形瓶:右手三指拿住瓶颈，瓶底离台约2,3cm，滴定管下端深入瓶口约1cm，c 同一方向圆周运动，边滴边摇动。 d、注意事项:滴定时，左手不能离开旋塞任其自流;眼睛注意落点周围溶液颜色的变化;开始时可稍快，最后加半滴。 左手操作活塞 酸管滴定操作 碱管滴定操作 (5)读数: a、装满或滴定完后，等1,2分钟再读数;若滴定速度较慢可等0.5,1分钟。 anning figure 2.6 in Yibin city, Central City urban development vision vision2 spatial pl-ation function of modern service and port equipment manufacturing, liquor, and other features and modern industry. 2.5long the city's main commercial, business, administrative, cultural and creative research and development in science and educyout ar belt. Dvn group in the upper reaches of the jinsha River along the river continues to the East to South stream groups, laharacteristic tour area and Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze Rivedong cthe area has both integrated urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangiver, River in the city. Multiple groups: the relatively compact area layout, each district consists of multiple groups, and the R : the Yangtze, jinsha River and minjiang rivers, cities in three rivers based on development along the Yangtze River, city onthe combined city, urban Group organization structure, set up a decentralized development patterns, building ... Three riverse city and culture series supporting role, with natural landscapes and green for the background, according to belt open development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whol-m a single radiationtiple groups frointensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, mul4 b、将滴定管从架上取下，用右手大拇指和食指捏住无刻度处，其他手指辅助，保持垂直，视线与凹液底部平行(深色溶液读两侧最高点);读取的数值必须记录至小数点后第二位。 (6)滴定结束: 滴定管内剩余溶液应弃去，洗净滴定管，并用蒸馏水充满，夹在夹上备用。 四、实验原理 NaOH具有强吸湿性，也容易吸收空气中的CO，常含有NaCO。因此，NaOH标准溶液223 2-只能用间接法配制。为了避免CO的影响，还需配制不含CO的NaOH溶液。 23 -12-配制不含CO的NaOH溶液常用的方法是将NaOH制成饱和溶液(浓度为18mol?L)。3 在这种溶液中NaCO几乎不溶解而沉淀下来。吸取上层清液，用无CO的馏馆水稀释至所232需要的浓度。 当少量NaCO存在对测定影响不大时，可称取比需要量稍多的固体NaOH，用少量水23 迅速洗涤2,3次，以洗去面的NaCO，倾去洗涤水，然后配制成所需浓度的溶液。或23 者称取所需要量的NaOH试剂，用CO的蒸馏水溶解、配制。 2 标定NaOH溶液的基准物质有邻苯二甲酸氢钾和草酸等。也可以用标准酸溶液标定。 1、用邻苯二甲酸氢钾(KHCH0)标定 844 邻苯二甲酸氢钾易得纯品，在空气中不吸水，容易保存，是标定NaOH溶液的较好的基准物质。使用前在100,125?烘2,3h。它与NaOH的反应为: COOHCOONaNaOH=====+HO2+COOHCOOK 化学计量点时溶液的pH?9.1，可选酚酞作指示剂。 2、用草酸(HC0?2H0)标定 2242 草酸易得纯品， 稳定性也好。但草酸溶液不够稳定，能自动分解成CO和CO，光照2和催化剂能加速分解，所以制成溶液后应立即滴定。 -2-5+草酸是二元弱酸(K=5.9×10，K=6.4×10，用NaOH滴定时，两级H同时被中和。 a1a2 HC0 + 2NaOH = NaC0 + 2H0 2242242 化学计量点时溶液pH?8.4，可选酚酞作指示剂。 五、实验步骤 1、进入，将实验要用到的有关仪器从仪器橱中取出，把玻璃器皿按洗涤要求洗涤干净备用。 city, Central City urban development vision vision 2 spatial planning figure 2.6 in Yibin-ervice and port equipment manufacturing, liquor, and other features and modern industry. 2.5rcial, business, administrative, cultural and creative research and development in science and education function of modern scommeupper reaches of the jinsha River along the river continues to the East to South stream groups, layout along the city's main d Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze River belt. Dvn group in therea aned urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangdong characteristic tour aultiple groups: the relatively compact area layout, each district consists of multiple groups, and the area has both integratity. Mr and minjiang rivers, cities in three rivers based on development along the Yangtze River, city on the River, River in the croup organization structure, set up a decentralized development patterns, building ... Three rivers: the Yangtze, jinsha Riverban Gy and culture series supporting role, with natural landscapes and green for the background, according to the combined city, uopen development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whole citbelt -tiple groups from a single radiationintensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, mul5 -12、计算配制0.1mol?LNaOH 500ml所需固体NaOH的量。 用洁净而干燥的表面皿在台式天平上称取2gNaOH(NaOH固体具有强腐蚀性，容易腐蚀称量纸)。 迅速置于100mL烧杯中，用约2mL蒸馏水迅速洗涤2次，以除去NaOH表面上少量的NaCO，加50mL蒸馏水，搅拌全部溶解，移入带橡皮塞的试剂瓶中(NaOH溶液能腐蚀玻23 璃，时间后，玻璃瓶塞打不开)，加水稀释至500mL，摇匀，贴标签备用。 3、用配制好的NaOH溶液润洗洗涤好的碱式滴定管，然后装入NaOH溶液。 4、本次实验用HC0?2H0标定。 2242 回顾电子天平的使用及差减法称量的步骤。 准确称取HC0?2H0 1.3,1.6g置于100mL烧杯中(要求使用NaOH溶液的体积在2242 20,30mL，而吸取的HC0溶液体积为25mL，根据反应计量关系得出HC0溶液的浓度范224224围，然后根据定容体积计算出HC0?2H0的称取量)，加30ml蒸馏水，小心搅拌使之2242 溶解，然后定量地转移入250mL容量瓶中，定容，摇匀。 用移液管移取草酸溶液25.00mL于250mL锥形瓶中(保证被吸取溶液的浓度不发生变化)，加2,3滴酚酞指示剂(反应产物为NaC0，其水溶液呈弱碱性，即滴定终点在224 弱碱性范围，故选择酚酞作指示剂;不能用甲基橙作指示剂，会使滴定结果偏低)，用 -10.1 mol?LNaOH溶液滴定至溶液呈粉红色且30s内不褪色为止(溶液吸收空气中的CO2，使溶液酸度增大，超出酚酞的变色范围，酚酞呈其酸式色)，记录NaOH溶液的用量。平行滴定3次。按下式计算NaOH标准溶液的浓度。 ，，2mHCO,2HO-12242，，cNaOH,(mol,L) MHCO，，，，,2HOVNaOHr2242 六、数据处理 草酸质量 /g 定容体积 /mL 移取草酸溶液体积 /mL NaOH初读数 NaOH终读数 用去NaOH体积 /mL -1c(NaOH) /mol?L r belt. Dvn group in the upper reaches of the jinsha River along the river continues to the East to South stream groups, laharacteristic tour area and Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze Rivedong cthe area has both integrated urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangiver, River in the city. Multiple groups: the relatively compact area layout, each district consists of multiple groups, and the R : the Yangtze, jinsha River and minjiang rivers, cities in three rivers based on development along the Yangtze River, city onthe combined city, urban Group organization structure, set up a decentralized development patterns, building ... Three riverse city and culture series supporting role, with natural landscapes and green for the background, according to belt open development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whol-m a single radiationtiple groups frointensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, mulanning figure 2.6 in Yibin city, Central City urban development vision vision2 spatial pl-ation function of modern service and port equipment manufacturing, liquor, and other features and modern industry. 2.5long the city's main commercial, business, administrative, cultural and creative research and development in science and educyout a6 -1平均值 /mol?L 相对平均偏差 七、注意事项 1、称取NaOH固体时，注意不要洒在操作台上，如有洒落，应及时处理。 2、NaOH具有强腐蚀性，不要接触到皮肤、衣服等。 3、配制NaOH溶液时，注意蒸馏水的取用量应当大体有数，用量筒取，不能用烧杯。 4、NaOH溶液试剂瓶上标签内容应包括:班级，姓名，名称，浓度，日期等。 测试题1、NaOH固体可用分析天平称量( )。 A. 正确; B. 错误 测试题2、可用HC0溶液滴定NaOH溶液，用甲基红作指示剂( )。A. 正确; 224 B. 错误 测试题3、为操作方便，可以把NaOH溶液先倒入小烧杯中，用小烧杯将NaOH溶液装入滴定管中( )。A. 正确; B. 错误 测试题答案:1、B ;2、B ;3、B ; city, Central City urban development vision vision 2 spatial planning figure 2.6 in Yibin-ervice and port equipment manufacturing, liquor, and other features and modern industry. 2.5rcial, business, administrative, cultural and creative research and development in science and education function of modern scommeupper reaches of the jinsha River along the river continues to the East to South stream groups, layout along the city's main d Hong Kong in group, consists of 17 groups. Band: modern features gathering along the Yangtze River belt. Dvn group in therea aned urban functions, and have their own characteristics and perimeter formation Li Zhuang, Li Zhuangdong characteristic tour aultiple groups: the relatively compact area layout, each district consists of multiple groups, and the area has both integratity. Mr and minjiang rivers, cities in three rivers based on development along the Yangtze River, city on the River, River in the croup organization structure, set up a decentralized development patterns, building ... Three rivers: the Yangtze, jinsha Riverban Gy and culture series supporting role, with natural landscapes and green for the background, according to the combined city, uopen development. Spatial structure of 2, the prominent cultural city protection elements on the development of the whole citbelt -tiple groups from a single radiationintensive development. (5) have different emphasis: for development, "with development, the emphasis on" way, from space, mul7