IMF Lab

Complete the ½ sheet on your way in Drill Complete the ½ sheet on your way in 1A – you do not need to complete the 2nd question!

Demo Water Acetone Styrofoam cup

Water vs. Acetone Water Polar Acetone Nonpolar

Styrofoam Made from polystyrene Nonpolar https://answers.yahoo.com/question/index?qid=20100120185258AAcWy7s

Like Dissolves Like Polar compounds tend to dissolve in polar solvents (like water) Non-polar compounds tend to dissolve in non- polar solvents **Know the saying – “Like dissolves Like” 

Agenda 1A - Demo Drill Pass back VSEPR Sheet No more grades are going in the gradebook for Quarter 1 Intermolecular Forces Lab (IMF) IMF Reading/Notes Complete for HW, if not done

Intermolecular Forces IMF are forces that act between stable molecules What are IMF Intermolecular Forces IMF are forces that act between stable molecules Dipole-Dipole Hydrogen Bonding Dispersion Forces

Molecular Weight Mass of a molecule As the weight increases, IMF increases

Surface Tension The stronger the intermolecular forces in the liquid, the greater the surface tension

Odor Strong odor indicates weak IMF because of lower vapor pressure compound can have an odor only when its vapor pressure is sufficient to supply a noticeable amount of vapor to the nose. If intermolecular forces are strong, vapor pressure is low, because molecules have less free energy in the solid or liquid than as vapor.

Evaporation Rate The stronger the intermolecular forces in a liquid, the slower the evaporation rate because the molecules are held together by stronger attractions. You should note that a liquid doesn't necessarily have to reach boiling point before evaporation can occur. Evaporation takes place all the time. 

Safety Goggles and lab aprons! Place bookbags on table/away from lab stations You will have 4 minutes at each station Make sure cap is back on the bottle ASAP!! Person who is handling the chemicals should wear gloves

When you are done… Answer analysis questions Place lab in the bin Login to class website and find the link to the Khan Academy article. Start taking notes on IMF.

Guiding Questions for Article What is the difference between intermolecular forces (IMF) and intramolecular forces? What is the relative strength of the intramolecular forces? What are the 3 types of IMF and when do they occur? Which IMF is the strongest and which is the weakest? How do forces of attraction affect properties of compounds?

What you do not finish for notes is HW! 