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

7. Question 7 [10 marks total] At 20 C, a cube of zinc (Zn) has an edge length of 10 cm. The mass of the cube is 7.14 kg. Lo=10cm 3. Calculate the density of zinc at 20 \"C. [2] The temperature of the block is changed to Tr. The percentage change in density, \"/oAp, is 4.1 \"/o. The linear coefcient of thermal expansion of zinc, om = 40 x 10'5 C" b. Calculate the density of the zinc at T1. [2] c. Calculate the edge length of the zinc cube at Tf. Give your answer in cm to 4 decimal places.[2] d. Calculate the value of T1. [4] PAGE 8 OF 11 6. Question 6 [10 marks total] a. Explain in your own words what specific heat capacity is. [2] A well-insulated calorimeter contains 200 g of water at a temperature of 5 C. A 75 g block of an "AlBeMet" alloy at a temperature of 300 C is added to the calorimeter. The system is allowed to reach thermal equilibrium. (Cwater = 4.18 J g-1 .C-1, Calloy = 1.51 J g-1 .C-1) b. Calculate the final temperature of the alloy and water. [4] In a separate experiment, a well-insulated calorimeter contains 200 g of water at a temperature of 5 C. To the calorimeter, 75 g of the "AlBeMet" alloy and an unknown mass of gold are added. Both the alloy and the gold have an initial temperature of 300 C. The system is allowed to reach thermal equilibrium. The final temperature is 46 .C. (Cgold = 0.13 J g-1 .C-1) c. Calculate the mass of gold added to the calorimeter. [4] PAGE 7 OF 115. Question 5 [10 marks total] When a material changes phase, heat is either absorbed or released. a) The enthalpy of vaporization (AHvap) is the heat associated with vaporization (liquid > gas). Is AHvap positive, negative, or equal to zero? Explain your reasoning. [2] A 20 g sample of an unknown material is initially at a temperature of -10 C and solid. The sample absorbs 15700 J of heat and reaches a final temperature of 100 C, where it is a gas. Some useful constants are included in the table below. Constant Value Units Specific heat capacity of the solid, Csolid 1.60 Jgl C-1 Specific heat capacity of the liquid, Cliquid 2.20 Jg1 C-1 Specific heat capacity of the gas, Cgas 1.10 Jgl C-1 Melting point, Tm 10 OC Boiling point, To 85 .C Molar mass, M 80 g mol Heat of fusion, AHfus 10.2 KJ mol-1 b) Using the data in the table above, calculate the number of moles in the sample. [1] c) Using the data in the table above, calculate AHvap for the unknown material. Give your answer in kJ mol-. [7] PAGE 6 OF 118. Question 8 [10 marks total] A mercury thermometer displays a linear relationship between temperature and height of mercury about the thermometer bulb. The thermometer is calibrated using two points: a When the thermometer is placed in a solution at 10 C, the height of the mercury above the bulb is 12 mm. a When the thermometer is placed in a solution at 160 00, the height of the mercury above the bulb is 136 mm. When the thermometer is placed in a solution at a different temperature, the height of the mercury above the bulb is 118 mm. a. Calculate the temperature of the solution when the height of the mercury above the bulb is 118 mm. [5] At 25 C, a block of steel is constrained so that its length cannot change. At 25 C, there is no stress within the block. b. If the block is heated to the same temperature that you found in part (a), will the block break? Show calculations that support your answer. [5] Clsteel = '18 X 10'6C'1, E = 200 GPa, Gmax = 200 MPa PAGE 9 OF 11