CHEM 1011 - Week 4 Questions With Complete Solutions

NON-IDEAL GASES & RAOULTS LAW The ideal gas laws are made up of 2 assumptions. What are they? correct answer: - there is no attractive force between atoms or molecules. - the volume of the gas itself (atoms or molecules) is negligle. What are ideal and real gases? correct answer: - Ideal gases do not have volume and there are no forces between gas molecules. - Real gases do have volume, e.g. halogens Florine, chlorine, bromine, iodine. What is electronegativity? correct answer: a measure of the tendency of an atom to attract a bonding pair of electrons How do we asses how real gases deviate from ideal behaviour? correct answer: We plot the ratio PV/nRT against P. For an ideal gas this should always be 1. What are intermolecular forces? correct answer: forces between molecules, including forces of attraction or repulsion. What is the purpose of van der Waals equation? correct answer: An equation of state that generalises the ideal gas law based on plausible reasons that real gases do not act ideally. Basically just rearranging the equation to that it applies to real gases. In the van der Wall equation, what does a and b stand for? correct answer: A: reflects the strengths of intermolecular forces. The larger the a, the stronger the intermolecular forces. b: reflects molecular/atomic size. The larger the b, the bigger the gas and the smaller the free volume. Both melting and boiling points can be used as measures of