Q4/ An iron cube at a temperature of 300 °C is dropped into an insulated bath containing 20 kg water at 35°C. The water finally reaches a temperature of 50°C at steady state. Given that the specific heat of water and iron are equal to 4186 J/kg, K and 462 J/Kg, K respectively. Find the entropy changes for the iron cube and the water. Is the process irreversible? If so why?

3 moles of O2 at 1 atm and 500K expands isothermally to 0.3 m3. What is the change in entropy of the gas? a) 22.23 J/K            b) 7.41 J/K          c) -7.41 J/K         d) -22.23 J/K

Homework 6 Problem 4:   A mass m of water is heated reversibly from temperature T1 to T2 at a constant pressure of P. In this problem, we are going to determine an expression for the change in entropy, ΔS.Assume we can heat the given water infinitesimally slowly so that the process is reversible. Therefore, heat in any infinitesimal step is given by the following: dQ = mc dT, where c is the specific heat and is constant. Part (a)  Write an expression for the change in entropy ΔS for the system.  Part (b)  Calculate the change in entropy in cal/K for a sample of water with mass m = 1.6 kg and changing temperature from T1 = 25.6°C to T2 = (25.6+10)°C. The specific heat c of water is 1,000 cal/kg/K. ΔS = ______

A 9.50-mol sample of H, gas is contained in the left side of the container shown below, which has equal volumes on the left and right. The right side is evacuated. When the valve is opened, the gas streams into the right side. Valve H2 Vacuum (a) What is the entropy change of the gas? J/K (b) Does the temperature of the gas change? Assume the container is so large that the hydrogen behaves as an ideal gas. O The temperature does not change. O The temperature decreases. O The temperature increases.

Water is slowly warmed from 25.0°C to 80.0°C. If the mass of the water is 240 g, what is the water's entropy change (in J/K)? 176.02 How is an infinitesimal heat input dQ related to the temperature change of the water? Can you use this to write an expression for the infinitesimal entropy change dS which can be integrated? J/K

Which of the following statements is false? No heat engine can be more efficient than a Carnot engine working between the same reservoirs. The change in thermal energy of a heat engine that has completed one cycle is zero. Heat can flow spontaneously from a hot reservoir to a cold one. The entropy of an isolated system must decrease with time. Question 23 4 pts On a hot summer's day, you will feel cooler if you wear a light-colored shirt rather than a dark-colored one. This is due to the difference in the objects' densities. emissivities. thermal conductivities. Question 24 4 pts The thermal conductivity of concrete is 0.80 W/(m K), and the thermal conductivity of a certain type of wood is 0.10 W/(m K). How thick would a solid concrete wall have to be to have the same rate of heat flow as an 8.0-cm-thick solid wall of this wood? Both walls have the same surface area and the same interior and exterior temperatures. 16 cm 32 cm 64 cm O 1.0 cm Question 25 4 pts If the absolute temperature…

What is the change in entropy of the ice when a 0.050-kg ice cube at 0°C melts? The latent heat of fusion for water is 80 cal/g. Express your answer in calories per K. O infinite O 4000 cal/K O 4 cal/K O 10.7 cal/K O 14.7 cal/K

150 g liquid water at 80.0°C is placed in an insulated flask. A 12.0 g ice cube at 0°C is added to the water in the flask to form a system of ice + water. (a) What is the equilibrium temperature of the system?  (b) What is the net entropy change of the ice + water system as it reaches equilibrium?  Data for the physical properties of water are available on the formula sheet.

Consider two ideal gases, A and B. First, 10 moles of A are mixed with 10 moles of B.  Then in a second step, 10 moles of B are added to this mixture. Calculate the entropy of mixing for both steps.

A 2.00-L container has a center partition that divides it into two equal parts as shown. The left side contains 0.044 0 mol of H2 gas, and the right side contains 0.044 0 mol of O2 gas. Both gases are at room temperature and at atmospheric pressure. The partition is removed, and the gases are allowed to mix. What is the entropy increase of the system?