【单选题】______ plants, which manufacture their own food, animals obtain nourishment by acquiring and ingesting their food.
【多选题】用三线 -八线译码器和辅助门电路实现逻辑函数Y= ,则辅助门应 。
【判断题】用双硫腙光度法测定Pb2+, Pb2+的浓度为0.08mg/50mL,用2cm比色皿在520nm下测得T=53%,经计算,ε=8.9×103L·mol-1·cm-1。
【单选题】Successful education is the acquiring of knowledge from ______.
A.
classrooms, laboratories and museums
C.
intimate association between beginners
【简答题】用双硫腙光度法测定Pb 2+ ,Pb 2+ 的浓度为0.080mg/50mL,用2.0cm比色皿在520nm下测得T=53%,求吸光系数a和ε。
【简答题】________ evidence that language-acquiring ability must be stimulated. A) If being B) It is C) There is D) There being
【简答题】用双硫腙光度法测定Pb 2+ ,Pb 2+ 的浓度为0.08mg/50cm 3 ,用2cm比色皿在520nm处测得T=53%。求k=?(Pb原子量207.2。)
【单选题】螺旋传动中的螺母多采用青铜材料,这主要时为了提高_________的能力。
【简答题】用双硫腙光度法测定 Pb 2+ 。 Pb 2+ 的浓度为 0.08mg / 50 mL ,用 2cm 比色皿在 500nm 下测得 T =53 %,求 κ 。