【单选题】If solutions of calcium iodide and ammonium chloride are mixed together in a metathesis reaction, what is the empirical formula for the precipitate which forms ?
E.
A mixture of NH 4 Cl and CaCl 2 forms
【简答题】Calculate the approximate pH value of different solutions below ; (1) A 0.10 M HAc K a (HAc)=1.8×10 -5 (2) A 0.10 M NH 4 Cl K b (NH 3 )= 1.8×10 -5 (3) A mixture solution with 0.05 M NaHCO 3 (50 mL...
【单选题】( )摩擦驱动装置联轴器连接的两轴同轴度应符合规定。
【简答题】What volume of 0.1mol/L hydrochloric acid solution should be added to 50 mLof the following solutions respectively to prepare solution at pH =7.00? (1) 0.1mol/L NaOH solution. (2) 0.1 mol/L NH3 soluti...
【单选题】If the following solutions are at the same concentration of 0.1 mol · L -1 , which is the correct ordering of their pH value? ( Ka( HAC )=1.75 × 10 -5 , Ka( HF )=6.8 × 10 -4 , Ka( HCN )=6.2 × 10 -10 )
A.
NaCN >NaAc>NaF>NaCl>NH 4 Cl
B.
NaF>NaAc>NaCN> NaCl>NH 4 Cl
C.
NaAc>NaCN>NaF>NaCl>NH 4 Cl
D.
NH 4 Cl>NaCl>NaF>NaAc>NaCN
【判断题】清政府为了管理中俄边境地带,先后设立了很多的卡伦(边防哨所)。
【多选题】当前中小学教师违法执教的教师自身的原因有哪些
A.
损害学生的身心健康,侵犯学生的受教育权的部分教师是因为法律是知识欠缺