Zhikai IdealGas - PC1221 Lab Report: Ideal Gas Laws| PC1221...

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PC1221 Lab Report: Ideal Gas Laws|| ||Wang Zhikai|| ||A0080959N|| ||Group A1|| PC1221 Lab Report: Ideal Gas Laws|| ||Wang Zhikai|| ||A0080959N|| ||Group A1|| 1 Objectives To demonstrate that the pressure P of a gas at a fixed temperature is proportional to the quantity (1/ V ) where V is the gas volume. To demonstrate that the volume V of a gas at a fixed pressure is proportional to the temperature T of the gas. To determine an experimental value for the constant that relates Celsius temperature T C to the absolute temperature T . To determine an experimental value for the atmospheric pressure Pa. 2 Introduction All gases can be described by the three variables of volume V , pressure P and temperature T . If we assume that the density of the gases is low, we call the gas in question an ideal gas. Although there are no true ideal gases, most gases behave to a good approximation as ideal gases near room temperature and atmospheric pressure. The ideal gas law is given by PV = nRT , where n is the number of moles for the gas and R is the universal gas constant with a value of 8.31441 JK -1 mol -1 . The SI units of pressure P are N/m 2 and the SI units of volume V are m 3 . When using this equation, the temperature is always expressed as the absolute temperature in Kelvins. The relationship between temperature in Celsius T C and the absolute temperature in Kelvins T is given by the equation T = T C + T O . However, each Kelvin is similar in magnitude to Celsius; therefore the difference in temperature is the same whether it is in Kelvins or Celsius. Using the ideal gas law, we can create several scenarios where we keep one of the three variables describing air as a constant in order to vary the other two to obtain experimental values for the constants involved in the law. We can keep the amount of air quantity fixed at a constant temperature. With the amount of air fixed, n is a constant, and with the temperature fixed, so is T . Thus, we can designate nRT as a constant C 1 . We can then rewrite the ideal gas law equation as P = C 1 (1/ V ), also known as Boyle’s Law. In order to vary the pressure of the gas, we use a measuring tube with mercury in it and compare the height difference between the height of the mercury in the measuring tube and the mercury level in the reservoir. For us to measure the pressure of the gas in a measuring tube, we can divide the pressure P in the measuring tube into two parts, the atmospheric pressure P a and the additional pressure as the gauge pressure P g . P g is caused by any height difference h between the two mercury levels and is calculated with the equation P g = p gh and is given as 0.1333kN/m 2 mm -1 h . By substituting P a + P g for P in Boyle’s Law, we obtain P g = C 1 (1/ V ) - P a . When we consider the situation with a fixed amount of gas and a constant pressure
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Zhikai IdealGas - PC1221 Lab Report: Ideal Gas Laws| PC1221...

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