Friction. That was the topic Sally and Sue are investigating in science. They used a small car and a ramp as seen in the picture above. They knew that they slipped easily on waxed floors but not on carpet, so they decided change the
material on the surface of the ramp. They planned to use glass, carpet, aluminum foil, and sandpaper and run the car
down the ramp over each surface. The girls wrote a research question: Do rougher surfaces tend to create more
friction than smoother surfaces? They predicted that the greater the friction, the slower the car would travel down the
ramp
What would be the BEST hypothesis for their experiment?
A)
The smoother the ramp surface, the greater the car's speed.
B)
Heavier cars travel down the ramp faster than lighter cars.
The greater the angle of the ramp, the faster the car will move.
D)
Without lubrication, the car will travel slowest down the sandpaper
covered ramp.

Straightforward questions answered in the powerpoint slidesreaction: heating the starting materials under refluxwhat does it mean to heat under reflux? why do we choose water as the reflux solvent? what are boiling chips used for? why do we put a condenser on top of the reaction? why do we add heat and let the reaction stir for 30 minutes? why do we add sulfuric acid to the reaction after it cools as opposed to when it’s still hot? separation: filtration of precipitatewhy don’t we do an aqueous and organic extraction in the separatory funnel? why do you rinse the salicylic acid on the filter with ice cold water? purification: recrystallization of salicylic acid (no hot filtration needed)what is the difference in the amount of room temperature water vs. boiling water needed to dissolve the salicylic acid (assume a 1.2 gram yield of salicylic acid)? remember, in the lab if you need x ml of boiling water to dissolve a solid, then you should add a little more (definitely no more than 1.5 times the theoretical amount) to ensure it doesn’t recrystallize prematurely.analysis: melting point of salicylic acidwhat can you conclude if the melting point of the salicylic acid you just synthesized is 152-155oc and the 1: 1 mix of your product and “synthetic” salicylic acid is 151-154oc?

In apex! a liquid heated beyond a certain temperature becomes

How does the motion of particles in a gas change as the gas cools