A student dissolves of in of water in an insulated coffee-cup calorimeter
CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics
Problem
A student dissolves 4.0g of NH4NO3(s) in 100mL of water in an insulated coffee-cup calorimeter. The molar enthalpy of dissolution of NH4NO3 is reported as +25kJmol−1. Which observation is most consistent with this information?
(a) The temperature remains essentially unchanged because the quantity of heat involved is too small to affect the water.
(b) The temperature of the water decreases because the process absorbs heat from the solution.
(c) The temperature of the water increases because the process releases heat to the surroundings.
(d) The calorimeter lid warms noticeably because heat flows from the surroundings into the system.