问题:单选题下列分子中能产生紫外吸收的是()A Na2OB C2H2C CH4D K2OE NaCl...
Tuesday, July 29, 2025
问题:我国《生活饮用水卫生标准》规定汞浓度不得超过()。...
Friday, September 16, 2022
Friday, September 16, 2022
Thursday, September 22, 2022
Thursday, September 22, 2022
Friday, September 23, 2022
Thursday, September 22, 2022
问题:邻二氮菲比色法测铁是在什么条件下Fe2+与邻二氮菲生成橙红色化合物()。...
Sunday, September 18, 2022
Thursday, September 15, 2022
Thursday, September 22, 2022
问题:用重铬酸钾标定硫代硫酸钠溶液时,以下操作步骤中,错误的是( )。...
Thursday, September 22, 2022
问题:用火焰原子吸收光谱法测定化妆品中铅,当样品中含有大量Fe时,Fe283.34nm和283.25nm谱线对Pb283.3n...
Thursday, September 22, 2022
Wednesday, September 21, 2022
Thursday, September 22, 2022
问题:单选题适用于一般化学分析的试剂标签颜色是( )。A B C D E...
Monday, August 14, 2023
问题:单选题测定食品中的硒,消化处理至终点冷却后,为使六价硒还原成四价硒,需要加入以下哪种物质后继续加热()A 硫酸B 盐酸C 硝酸D 氰溴酸E 高氯酸...
Monday, April 14, 2025
问题:对于每种采样方法,选择合适的滤料是保证采样效率的一个主要因素,以下哪种滤料不宜用作重量法测定悬浮颗粒物?()。...
Tuesday, September 20, 2022