Answer:
Endothermic
Explanation:
The temperature of the water decreased.
The water lost heat.
The heat must have gone into getting the KNO₃ into solution.
So, the dissolving of KNO₃ in water is endothermic.
Answer:
emf generated by cell is 2.32 V
Explanation:
Oxidation: 
Reduction: 
---------------------------------------------------------------------------------
Overall: 
Nernst equation for this cell reaction at 
-
![E_{cell}=E_{cell}^{0}-\frac{0.059}{n}log{[Al^{3+}]^{2}[I^{-}]^{6}}](https://tex.z-dn.net/?f=E_%7Bcell%7D%3DE_%7Bcell%7D%5E%7B0%7D-%5Cfrac%7B0.059%7D%7Bn%7Dlog%7B%5BAl%5E%7B3%2B%7D%5D%5E%7B2%7D%5BI%5E%7B-%7D%5D%5E%7B6%7D%7D)
where n is number of electrons exchanged during cell reaction, 
is standard cell emf , 
is cell emf , ![[Al^{3+}]](https://tex.z-dn.net/?f=%5BAl%5E%7B3%2B%7D%5D)
is concentration of 
and ![[Cl^{-}]](https://tex.z-dn.net/?f=%5BCl%5E%7B-%7D%5D)
is concentration of 
Plug in all the given values in the above equation -
![E_{cell}=2.20-\frac{0.059}{6}log[(4.5\times 10^{-3})^{2}\times (0.15)^{6}]V](https://tex.z-dn.net/?f=E_%7Bcell%7D%3D2.20-%5Cfrac%7B0.059%7D%7B6%7Dlog%5B%284.5%5Ctimes%2010%5E%7B-3%7D%29%5E%7B2%7D%5Ctimes%20%280.15%29%5E%7B6%7D%5DV)
So, 
Answer is: <span>excited state.
In </span>excited state, hydrogen has<span> higher </span>energy<span> than in the </span>ground state (state with lowest energy). H<span>ydrogen atom has one </span>electron<span> in the lowest possible </span>orbit<span> (1s), when atom absorbs</span><span> energy</span><span>, the electron move into an excited state (quantum numbers greater than the minimum possible). </span>Electron lifetime in excited state is short.
Answer:
use google and use the first link
Explanation:
The atomic radium increases to the left and downwards on the periodic table.
By that logic, Se has the largest radius.
