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As a table, come up with the big idea from yesterday’s computer activity. Use the ideas of electron density, bond polarity, and the polarity of a whole molecule . Write it on a mini white board and be prepared to share it out loud. (does not need to go on lined paper). Warm-Up 1/14/14.
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As a table, come up with the big idea from yesterday’s computer activity. Use the ideas of electron density, bond polarity, and the polarity of a whole molecule. Write it on a mini white board and be prepared to share it out loud. (does not need to go on lined paper) Warm-Up 1/14/14
Bond and IMF Strength Monday 1/13/14
Intermolecular Forces (IMFs) hold molecules together! • The more IMFs between certain molecules, the more tightly they are held together. Review
IMFs have different strengths, which we can measure using “bond energy”—the energy it takes to break the attraction. Strongest Weakest Covalent bonds (400 kcal) Hydrogen “bonding” (12-16 kcal) Relative Strengths of IMFs Dipole-dipole interactions (2-0.5 kcal) Londonforces (less than 1 kcal)
IMFs make it hard to break molecules apart from one another. • Higher strengths/amounts of IMFs leads to: • High boiling points • Higher melting points • High surface tension • High viscosity (thickness) Effect of Intermolecular Forces
IMFs affect solubility: what will and won’t dissolve in a solution • Things with similar IMFs will dissolve in each other • Ex) Sugar dissolved in water: both allow for hydrogen bonding
Finish the questions on the IMF worksheet. • Reminder: QUIZ tomorrow • Polarity (like Electronegativity ChemQuest) • Intermolecular Forces (identifying and effects) Your Job