Q35Short answer
The relation between pressure exerted by an ideal gas (pideal) and observed pressure (preal) is given by the equation pideal = p real + 2 If pressure is taken in Nm–2, number of moles in mol and volume in m3, Calculate the unit of ‘a’. What will be the unit of ‘a’ when pressure is in atmosphere and volume in dm3?
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pideal = p real + 2 We write the known units in the above equation. –2 –2 a . mol Nm = Nm + 3 2 (m ) If two values with same units are added then the units of result are same as added units. -2 a .mol ∴ Nm = 6 –2 6 Nm .m a = 2 a = Nm4 mol–2 Similarly, when p is in atm and volume in dm3 3 2 atm(dm ) a = 2 = atm dm6 mol–2