- A piece of solid lead weighing 38.9 g at a temperature of 318 °C is placed in 389 g of liquid lead at a temperature of 369 °C. After a while, the solid melts and a completely liquid sample remains. Calculate the temperature after thermal equilibrium is reached, assuming no heat loss to the surroundings.
The enthalpy of fusion of solid lead is ΔHfus = 4.77 kJ/mol at its melting point of 328 °C, and the molar heat capacities for solid and liquid lead are Csolid = 26.9 J/mol K and Cliquid = 28.6 J/mol K.
9.When a zirconium bar of mass m is dropped through a height difference Δh, its potential energy changes by the amount mgΔh, where g is the acceleration of gravity, equal to 9.81 m s-2. Suppose that when the bar hits the ground, all that energy is converted to heat, increasing the temperature of the bar. If the specific heat capacity of the material in the bar is 0.278 J K-1 g-1, calculate the height from which the bar must be dropped to increase the temperature of the bar by 2.60 °C.
3.The standard enthalpy change of combustion [to CO2(g) and H2O()] at 25°C of the organic solid heptadecanoic acid, C17H34O2(s), is determined to be -10605.6 kJ mol-1. What is the Hf° of C17H34O2(s) based on this value?
Use the following data: Hf° H2O () = -285.83 kJ mol-1 ; Hf° CO2(g) = -393.51 kJ mol-1
1)The temperature after thermal equilibrium is reached =... View the full answer