Answer : The reaction is endothermic.
Explanation :
Formula used :

where,
= change in temperature = 
Q = heat involved in the dissolution of KCl = ?
m = mass = 0.500 + 50.0 = 50.5 g
c = specific heat of resulting solution = 
Now put all the given value in the above formula, we get:


The heat involved in the dissolution of KCl is positive that means as the change in temperature decreases then the reaction is endothermic and as the change in temperature increases then the reaction is exothermic.
Hence, the reaction is endothermic.
Answer:
Due to the lack of context for your question I’m not completely sure which you are talking about but NH can be Imidogen or it could be ammonium which is NH4^1+
Answer:
B. temperature decreases as altitude increases.
Explanation:
Just like in the lower reaches of the atmosphere, the troposphere, in the mesosphere, temperature decreases as altitude increases.
The mesosphere is the third layer of the atmosphere just above the stratosphere.
- It begins at the top of the stratosphere and ends at the mesopause where the thermosphere begins.
- The mesosphere is often referred to as the middle layer.
With increasing height, the temperature of the mesosphere decreases significantly. The top of the mesosphere is one of the coldest part of the earth atmosphere. This is as a result of increasing atmospheric cooling by carbon dioxide in this region of the atmosphere.
Chlorine is the most electronegative