The hydrogenation of unsaturated hydrocarbons is
an important industrial process. Precious metals,
such as platinum and palladium, can greatly
increase the rate of this reaction. During this
process, the gaseous reactants are pumped
across a layer of metal powder. An example of this
process is shown below.
Describe how the metal probably increases the
reaction rate, identify whether this is an example of
homogeneous or heterogeneous catalysis, and
explain how you know.

You are performing an experiment in a lab to attempt a new method of producing pure elements from compounds. the only problem is that you do not know what element will form. by your previous calculations you know that you will have 6.3 moles of product. when it is complete, you weigh it and determine you have 604.4 grams. what element have you produced?

Hot air balloons float in the air because of the difference in density between cold and hot air. in this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. to do this, use the following variables and make these assumptions: the combined weight of the pilot basket together with that of the balloon fabric and other equipment is w. the volume of the hot air inside the balloon when it is inflated is v. the absolute temperature of the hot air at the bottom of the balloon is th (where th> tc). the absolute temperature of the cold air outside the balloon is tc and its density is ďc. the balloon is open at the bottom, so that the pressure inside and outside the balloon is the same. as always, treat air as an ideal gas. use g for the magnitude of the acceleration due to gravity.

What layer of the atmosphere is directly above the troposphere?