When an endothermic chemical reaction (the system) occurs inside a calorimeter containing water (the surroundings) and no heat escapes from the calorimeter, which of the following statements is true? a. Heat flows from the system to the surroundings and the temperature of the water increases.
b. Heat flows from the surroundings to the system and the temperature of the water decreases.
c. Heat flows from the system to the surroundings and the temperature of the water decreases.
d. Heat flows from the surroundings to the system and the temperature of the water increases.

b. Heat flows from the surroundings to the system and the temperature of the water decreases.

Explanation:

The laws of thermodynamics lets us know that energy is neither created nor destroyed but can be converted from one form to another. Also, energy transfer does accompany chemical reactions in the form of heat.

For an endothermic reaction, heat is absorbed by the system from the surroundings. This leads to a drop in the temperature of the surroundings as energy is removed.

This implies that the water temperature decreases.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.