^{Hi I need help with some basic physics homework plz. Thank you so much in advance}

. Question 3 [10 marks total] a. Calculate the change in internal energy of the system for the following processes: [2] i) 20 J of heat is released by the system. and 40 J of work is done on the system. ii) 460 J of heat is absorbed by the system. and the system does 50 J of work. A 4.8 mol sampte of an ideal gas expands from an initial state (P = 4 x '105 Pa, V = 0.02 m3) to a nal state (P = 1 x 105 Pa, V = 0.08 m3). The initial and final state are shown on the pressure-volume diagram below. Initial 400 Path 1 '6' n. 5, 2 :i m (I) 9 o. 100 0.02 0.08 Volume (m3) The gas can expand by: a Path 1: two step expansion. (Grey line) :- Path 2: isothermal expansion at T = 200 K. (Red line) b. Calculate the work done by the gas on path 1. [3] c. Calculate the work done by the gas on path 2. [3] d. Determine the value of Q for path 2 and state whether heat is absorbed or released. [2] PAGE 4 OF 11 1. Question 1 [10 marks total] A gas sample is made of a mixture of two ideal gases. The sample has a total pressure of 1.0 x 105 Pa and a volume of 0.040 m3 at a temperature of 80 C. a) Calculate the total number of moles of gas in the sample. [2] The gas mixture contains two gases: carbon dioxide (002) and neon (Ne). The mole fraction of Ne in the mixture is 0.34 (Km = 0.34). b) For the conditions given in part (a). calculate the density of the gas. Give your answer in glm3. [5] The temperature of the sample is increased to 150 OC. The volume and number of moles of gas remain constant. c) Calculate the new pressure of the gas sample. [2] d) State whether the density will increase, decrease, or remain the same. Explain your reasoning. [1] PAGE 2 OF 11 4. Question 4 [10 marks total] A cross-section of a building wall is shown below. The thickness of the wall is 20 cm. The inside of the building is kept at a temperature of 25 00. When the outside temperature is 2 EC, the heat flux through the wall is 138 W m'a. The wall is made from Material X. Material X is one of the materials listed in the table below. Material Thermal conductivity, k (W rn'1 K\") G" = 1'33 W m4 Brass 110 Tnnsrde = 25 0C Toulside = 2 C Steel 50 Super alloy 12 Stone 40 (> Concrete 12 Material X 20 cm Wood 02 a. Assuming steady-state conditions, calculate the thermal conductivity of the wall, and state the identity of Material X. [3] A different room has a wall that is made from two layers. Layer 1 is 10 cm thick and made from wood, layer 2 is 20 cm thick and made from stone. A simplified cross-section of the wall is shown below. The inside temperature is 25 '3C. and the outside temperature is 2 (3C. q\" Tinside = 25 0C ToutSIde = 2 ac (96) Wood Stone 10 cm 20 cm b. Assuming steady-state conditions, calculate the heat ux through the wall. [7] PAGE 5 OF 11 2. Question 2 [10 marks total] The ideal gas law and the van der Waals equation are shown below: Ideal gas law: PV : nRT van der Waals equation: Pm! : anZb _ a ($2 a) State the two main assumptions made about ideal gases. [2] There are two samples oi the same gas: sample A and sample B. Both samples contain 2 moles of gas and have a volume of 0.01 m3 but have different temperatures and pressures. The ideal pressure (Pidea) calculated using the ideal gas law is included in the table below. n (mol) V (m3) T (K) Pideal (Pa) Preal (Pa) Sample A 2 0.01 400 665120 ? Sample B 2 0.01 100 166280 ? b) Calculate the Pm. of each sample (a = 0.37 Pa ma moi", b = 8.2 x 10'5 m3 moi-1) [4] c) Calculate the percentage difference between Preal and Pideal for each sample. [2] d) State which sample behaves most Ideally. Explain your reasoning. [2] PAGE 30F 11