当a=0.5,b=4时,2a+3b的值是______.
当a=0.5,b=4时,
2a+3b,
=2×0.5+4×3,
=13.
答:2a+3b的值是13.
故答案为:13.
常温下,下列溶液中可能大量共存的离子组是( )
A.含有大量S2-的溶液:Na+、ClO-、Cl-、CO32-
B.含有大量Al3+的溶液:K+、Na+、AlO2-、SO42-
C.能使pH试纸变红的溶液:NH4+、Na+、NO3-、HCO3-
D.水电离产生的c(H+)=1×10-12mol•L-1的溶液:Mg2+、SO42-、NO3-、Cl-
--- Jack fell off the ladder yesterday, but he is all right now?
---What a lucky dog! He _________ himself badly.
A.should injure
B.might injure
C.should have injured
D.could have injured