Chem 112 Exam AID Course Pack

The same is true for any non polar substance in water

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: quid in the bottom right - we can also move around on the graph to see what increasing/decreasing pressure/temperature would do If you choose a temperature and pressure that puts you on the border between two phases (a coexistence line), the liquid is in equilibrium between those phases. If there is an equilibrium between three phases, you are at a triple point. The slope of the solid- liquid coexistence line for water is negative, but for most substances it is positive. (Why is this?) Ethan Newton & Barry Zhang for SOS Winter 2012 20 If you increase both temperature and pressure high enough along the liquid- gas line, the substance will reach the critical point (at the critical temperature and critical pressure) and become a supercritical fluid. The boundary between liquid and gas will disappear. - compressibility of a critical fluid tends to be 0.25 to 0.35 - the ratio of normal boiling point to critical temperature tends to be 0.58 to 0.65 Intermolecular forces indicate how strongly molecules resist being pulled apart; they are dependent on the arrangement of atoms in each molecule. From weakest to strongest, London dispersion forces - electrons gather by chance at one end of a molecule, creating a temporary dipole - this induces a temporary dipole in the next molecule over, resulting in an attraction for the short length of time the dipoles exist - found in all molecules - increase in strength with the size of the molecule (=greater probability of an asymmetric distribution) Dipole- dipole interactions - between polar molecules (which have permanent dipoles, as opposed to the temporary dipoles of London dispersion forces) - increase with the polarity of the molecule Hydrogen bonds - only occurs in liquids - an H bonded to N, O, or F is very electron- deficient since it’s beside such an electronegative atom - a lone pair on a neighbouring molecule will be attracted to the H - increases with the number of hydrogens bonded to N/O/F, and with the number of lone pairs on the molecule (Beyond these, we have molecules that associate ionically, and then molecules that associate covalently.) 6.0 Solutions − One substance is mixed with another, at the molecular level, until the overall (molecular) composition is uniform. A solution can be solid, liquid, or gaseous. − (If the substances are reacting with each other, you’re not really forming a solution). − Physical properties generally c...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online