Question

2. (15 marks) The van der Waals equation (first introduced by van der Waals in 1877) is an attempt to describe the fact that real gases do not follow the ideal gas law. According to this equation where P is the pressure of the gas, V is the volume, R is the gas constant, T is the temperature, n is the number of moles, and a and b are parameters that depend on the gas (a) Suppose that 1.0 ± 0.05 mole of oxygen was measured to have a volume of 22.0 ± 0.05 of the question)? You'll need to find values of a and b for oxygen. Look them up. (b) what are the absolute and relative errors m the calculation of P+詈? (That is, let (c) Suppose you have 1 mole of oxygen at 300 K. Write P as a function of V for oxygen. What is the scientific domain of P(V)? Plot P(V) (use any appropriate software. L at a pressure of 100 ±0.5 kPa, what is the temperature (ignore errors for this part P + īnī aid calculate Δα and g. Be careful: you need to do this in two steps.) Note a number of important things. i. Be very careful with the values you use for a and b. Your values need to be in the right units to match the other units in the equation. ii. When you do a plot you must label your axes properly, you must label all the curves on the graph, and the graph must be legible and acceptable resolution. (For example, a low-resolution screen shot isn't good enough.) You have to make sure you put all the units on the graph, also ii. You also have to choose the scales appropriately. Your graphing software won't do this for you, so you need to do it yourself. Choose the horizontal and vertical scales carefully to be scientifically reasonable and to illustrate features of the function. (d) On the same graph plot P(V) for a one mole of a perfect gas at 300 K. Comment on the differences. In particular, what are the differences between a real gas and an ideal gas at high pressures?

Answer 1

V-b 0 2969 28 03 dv 0.00 一0.001 o0 S