Question

A chemical reaction is endothermic if it absorbs heat from its surroundings. It is exothermic if it gives off heat to its surroundings. In her chemistry class, Lily is given a salt (ammonium nitrate) and a beaker of water at 60 °F She dissolves the salt in the water and sees that the temperature of the solution is now 50 °F. Did the temperature of the solution increase or decrease? By how many degrees? What kind of reaction has occurred?

The temperature increased by 10°F, and an exothermic reaction occurred.
The temperature increased by 10°F, and an endothermic reaction occurred.
The temperature decreased by 10°F, and an exothermic reaction occurred.
The temperature decreased by 10°F, and an endothermic reaction occurred.

Answer 1

The temperature of the solution decreased by 10°F, indicating that an endothermic reaction occurred as the system absorbed heat from the surroundings.

Step-by-step explanation:

When Lily dissolved ammonium nitrate in water, and the temperature dropped from 60 °F to 50 °F, the temperature of the solution decreased by 10°F. The reaction that occurred is an endothermic reaction, which means it absorbed heat from its surroundings, causing the temperature of the solution to decrease. In endothermic processes, the system (in this case, the solution) gains heat, and the sign of q (the quantity of heat) is positive, signifying that heat is being absorbed by the system from the surroundings.