Warm Up: Pg Work silently. Raise hand to ask Ms. Hughes anything. 1.Get a pink packet from the side shelves. 2.Do NOT write the question, only the answer. 3.Do NOT write in the packet. Write on a SEPARATE sheet. Label the warm up with the date. 4.This is GEE practice so you must put an answer for EVERY question even if it’s a guess. Leave NOTHING blank. 5.After time we will go over them. 6.When finished, put the papers in the CORRECT order.

Announcements Unit 5 test tomorrow (3/5) If you have not taken 4 chemistry tests yet this semester, see me after to arrange a make up Retake GLEs for GRADE BOOST 1 WEEK UNTIL END OF THIRD QUARTER!!!

Mystery Element Named for the sons of the Earth goddess in Greek mythology Very strong and very light Used in surgical pins and artificial hips 10,000lbs of it are used to make a Boeing 747

Take 1

Objective Identify and compare intermolecular forces and their effects Today we put it all TOGETHER!

Inquiry: no right or wrong!!! 1.What are intermolecular forces in general? 2.What do they do?

Intermolecular Forces Inter (between) Forces between molecules Think international = between countries 3 main types: –London dispersion forces –Dipole-dipole forces –Hydrogen bonds

Inquiry- no right or wrong! 1.What has stronger intermolecular forces: a solid or a gas? 2.Very strong intermolecular forces will cause: a high boiling point or a low boiling point? 3.Very strong intermolecular forces will cause: high surface tension or low surface tension?

Surface Tension Experiment Procedure: Observe the effect detergent has on paper clip floating in water Materials: beakers, water, paperclips, detergent Observations: ? Conclusion: thoughts about why???

Surface Tension Experiment Procedure: Observe the effect detergent has on paper clip floating in water Materials: beakers, water, paperclips, detergent Observations: paperclip fell through surface when detergent added (surface LESS tense) Conclusion: pure water had stronger surface tension, detergent disrupted it, thoughts about why? –Why does water have strong surface tension? –Why did detergent disrupt it?

Possible answers to come…

London dispersion forces Weakest Caused by movement of electrons around nucleus and temporary slight charges Between both POLAR and NONPOLAR molecules

Dipole-dipole forces Medium strength Caused by attraction between the permanent slight negative and positive charges on the ends of polar molecules Between POLAR molecules

Hydrogen bonds Strongest Stronger form of dipole-dipole forces Caused by attraction between very polar molecules with large slight positive and negative charges at either end Between molecules with –Hydrogen (H) and –either Nitrogen (N), Oxygen (O) or Fluorine (F)

Effects of intermolecular forces Stronger forces cause molecules to be… closer together or farther apart?

Effects of intermolecular forces Stronger forces cause molecules to be… closer together!!!

Effects of intermolecular forces Stronger forces cause molecules to be… Solids or gases?

Effects of intermolecular forces Stronger forces cause molecules to be… Solids!

Think back… What’s a boiling point? Melting point? Boiling point- Melting point-

Think back… What’s a boiling point? Boiling point –the temperature to reach to boil (change from liquid to gas or in other words…SPREAD OUT)

Think back… What’s a melting point? Melting point – the temperature to reach in order to melt (change from solid to liquid or in other words…SPREAD OUT)

Effects of intermolecular forces Stronger forces cause molecules to have… An easier time or a harder time spreading out?

Effects of intermolecular forces Stronger forces cause molecules to have… a harder time spreading out!

Effects of intermolecular forces Stronger forces cause molecules to have… a higher or a lower boiling point?

Effects of intermolecular forces Stronger forces cause molecules to have… a higher boiling point!

Effects of intermolecular forces Stronger forces cause molecules to have… a higher or a lower melting point?

Effects of intermolecular forces Stronger forces cause molecules to have… a higher melting point!

Summary Stronger forces Molecules closer together Solid High melting point High boiling point Weaker forces Molecules farther apart Gas Low melting point Low boiling point

What intermolecular forces (or IMF) exist between the following molecules? May be more than one… 1.H 2 O 2.O 2 3.HCl 4.HF 5. NH 3 6. CO 2 7. N 2 8. HBr Remember: Polar if different elements (thus different strengths) for 2 elements compounds Polar if asymmetrical for +2 compounds

Which substance is more likely to be a solid? #1 or # 2 #5 or #6 #7 or #8

Which substance is more likely to be a solid? #1 #5 #8

Which substance is more likely to have a lower boiling point? # 2 or #3 #3 or #4 #5 or #7

Which substance is more likely to have a lower boiling point? # 2 #3 #7

Complete the “IMF Practice” sheet

IMF foldable mini-project Materials: –Construction paper –Markers –Instructions + rubric sheet –Notes from today’s lecture To start, pay attention to how to fold and cut the paper Due at the end of class, worth half a test! Turn in your foldable AND worksheet!

Done Early? Start on homework Conferences Make up work Work quietly, be respectful

Sum up What did we learn today? HW: –“Review Sheet for Unit 5: Bonding” Top Ten: How’d we do?