0.5m氢氧化钠怎么配制
0.5mol/l 氢氧化钠溶液如何配制 氢氧化钠标准溶液配制与标定 一、 配制: 将氢氧化钠配成饱和溶液, 注入塑料桶中密闭放置至溶液清亮, 使用 前以塑料管虹吸上层清液。 浓 度 氢氧化钠饱和溶液 注入不含CO2的水 0.1mol/L量取5ml1000中摇匀 0.2mol/L 量取 10ml1000 中摇匀 0.5mol/L 量取 26ml1000 中摇匀 1.0mol/L 量取 52ml1000 中摇匀 二、 标定: 1、 原理: KHC8H4O4+NOH→KNaC8H4O4+H2O 酸式酚酞 碱式酚酞 HIn→In-+H+ (无色) (红色) 酚酞为一有机弱酸, 在酸性溶液中为无色, 当碱色离子增加到一定浓 度时, 溶液即呈粉红色。 2、 仪器: 滴定管 50ml; 三角瓶 250ml。 3、 标定过程 0.1mol/LNOH 标准溶液称取 0.4-0.6 克; 0.2mol/L 称 1-1.2 克;0.5mol/L 称取 3 克于 105-110℃烘至恒重的苯二甲酸氢钾, 称准至0.0002 克, 分别溶于 50ml; 80ml 不含二氧化碳水中,加 2 滴 1%酚酞指示剂, 用配好的待标定溶液至溶液呈粉红色与标准色相同。 同时作空白试验。 4、 计算: m C(NaOH) =---------------- (V1-V2)*0.2042 C(NaOH)---氢氧化钠溶液浓度 m——苯二甲酸氢钾之质量(克) V1——氢氧化钠溶液用量(毫升) V2——空白氢氧化钠溶液用量(毫升) 0.2042——与 1.000mol/LNOH 标准溶相当的以克表示的当量苯二甲酸 氢钾之质量 5、 注意事项: 1、 为使标定的浓度准确, 标定后应用相应浓度盐酸对标。 2、 液溶有效期 2 个月。 3、 氢氧化钠饱和溶液之配制: 于 1000 硬质容器中,加 70 毫升水, 逐渐 加入 700 克氢氧化钠。 随加随搅拌, 使溶解完全冷却后移入盛氢氧化钠饱和液之试药瓶中, 以胶塞密塞, 静置 7 天以上, 使含之碳酸钠沉淀完全。 取澄清之氢氧化钠饱和液少许, 加水稀释, 加氢氧化钡饱和液 1 毫升,十分钟内不产生浑浊, 表示碳酸钠已沉淀完全。
"以下是一篇关于介绍深圳旅游景点的英语作文,可以介绍欢乐谷 锦绣中华,民俗文化村,世界之窗啊等等: Shenzhen is one of China's top tourist destinations, attracting millions of visitors each year. Its pleasant seashore and well-preserved forests have made<br>-----------------------------------------------------------------------------------------------------<br>Shenzhen is one of China's top tourist destinations, attracting millions of visitors each year. Its pleasant seashore and well-preserved forests have made up for its lack of stately mountains and rivers, and earned it the title of ""International Garden City.""<br>Another magnet comes from its theme parks, with a great variety of features ranging from folk culture to a retired aircraft carrier. Distinctive sceneries, fabulous shows and stunning experiences: the parks' charms never seem to fade.<br>And don't forget this is a modern metropolitan, where high-rise buildings and green space intermingle perfectly. It is a financial center, a transportation hub, and home to many first-rate hotels and restaurants. Here you will never fail to find a cuisine that arouses your appetite and curiosity,<br>For tourists, this is a city of convenience, leisure and endless fun.<br>Theme Parks in the Overseas Chinese Town A magnet for tour groups, the Overseas Chinese Town (Hua Qiao Cheng) in Nanshan District features four distinctive theme parks sitting side by side. A monorail commutes around the parks in the area<br>Chinese Folk Culture Villages<br>Right next to Splendid China, the folk culture park dazzles with the histories and mysteries of the country's ethnic groups. Scattering around the 180,000-sqm park are 24 villages built in 1:1 ratio, inhabited by real ethnic people who present their traditional arts, customs, languages and cuisines. Traditional culture performances are held there every day. Like Splendid China, the park is also heavily forested.<br>Happy Valley<br>This is a place for kids and families. Usually packed on weekends by families, the fun park offers more than 100 attractions ranging from the thrilling Space Shot to the lovely cartoon-themed<br>events. It also holds daily performances of various themes.<br>Window of the World<br>Like Splendid China, this 480,000-sqm park features more than 130 miniature replicas of scenic and cultural wonders. The difference is that these are landmarks from all over the world. Here you can find the Golden Gate Bridge and the Niagara Waterfall of the United States, the Kremlin of Russia, Italy's Pisa Tower, Egyptian pyramids, the Taj Mahal of India and an Eiffel Tower built in 1:3 ratio.<br>Although these replicas would probably not attract Western visitors much, the park's daily dance performance and regular carnival-like events are of great fun. Beautifully illuminated at night, it is also an impressive city scene."