Question

Part A:

When a solid dissolves in water, heat may be evolved or absorbed. The heat of dissolution (dissolving) can be determined using a coffee cup calorimeter.

In the laboratory a general chemistry student finds that when 2.79 g of NH₄Cl(s) are dissolved in 106.00 g of water, the temperature of the solution drops from 23.17 to 21.34 °C.

The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.76 J/°C.

Based on the student's observation, calculate the enthalpy of dissolution of NH₄Cl(s) in kJ/mol.

ΔH_dissolution =  kJ/mol

Part B:

When a solid dissolves in water, heat may be evolved or absorbed. The heat of dissolution (dissolving) can be determined using a coffee cup calorimeter. In the laboratory a general chemistry student finds that when 2.70 g of FeBr3(s) are dissolved in 106.10 g of water, the temperature of the solution increases from 25.17 to 28.20 °C. The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.61 J/°C. Based on the student's observation, calculate the enthalpy of dissolution of FeBr3(s) in kJ/mol. Assume the specific heat of the solution is equal to the specific heat of water. ΔHdissolution =  kJ/mol

Answer 1

PART- A weizet de tyd 24720 M.ut Ntu-51.49 1 T23-172 -216.17K Temptrtuore ds Tr ssuten Ta= 21342-4.34 hecd apcityce = 176 Je Enthelpy atyel Sx(T2-71)x Ma 126 (24-24-A1)x539 2.79 -61-74 md = -G1-74X16md EnTLalay diufientlcls is-61-743h PART-IR t f FeBr= 2.79 11 TI 2517 TK Te-28.2c -301.2ok Enteloy & Lidution Fesr 161 X C301-20-812)x25 2-2 533.10 Jmd - 533 (0 y10 Kns