Destroyer 2010 GC help!!

[flin5845]

Ok I am confused with the wording on this question, and was hoping someone can clarify. Destroyer 2010 #52

What statement is true?
A. Temp is a measurement of the average kinetic energy.
B. 30 mL of water @ 70C has a greater average kinetic energy than 50mL @ 40C
C. When solid NH4NO3 is dissolved in water at @25C, the solution temperature decreases. This reaction is endothermic.
D. A and B
E. All of above

I put D. But the correct answer is E.

The explanation states that since the solution got colder, heat was absorbed, thus, the reaction is endothermic.

I am kinda confused. The solution was initially at 25C, then NH4NO3 was added and solution temperature decreased that means it went below 25C, therefore released energy, making it exothermic.

I thought that if something is endothermic it would absorb heat from the surroundings. So if something was at 25C, and NH4NO3 was added and the solution INCREASE, the solution would then be warmer relative to the surroundings because one it gained energy, and second energy was taken from the surroundings. But the question said the solution temperature decreased.

Can someone try to explain this?

Edit: # 66. This question is over graphing reaction rates. I do not understand the importance of the slopes. For example a 0 order reaction is [A] vs t and with a negative slope and therefore -k. However 1/[A] vs time is a 2nd order reaction with a positive slope and therefore a +k. I am trying to figure out the importance of knowing this stuff.

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[predental012]

The starting temperature without NH4NO3 was 25 degrees, so this is the amount of heat we start with. When NH4NO3 was added to the solution, the reaction that occurred in the solution needed to use heat as a reactant; it needed to absorb heat in order for the reaction to occur. Some heat from the surroundings was taken in by the reaction, thereby decreasing the temperature of the system/solution. Hope that makes sense that's how I pictured it

 

[skyway34]

Here's how I thought of it:

the solution's temp was already at 25. When the reaction took place, it used up heat, which in-turn lowered the temperature of the solution. So if heat was used up, as opposed to given off, the rxn must be endothermic.