This is a long one so bear with me. 1. How much aluminum oxide in grams is produced from the reaction of 3.5 moles of oxygen with 4.5 moles of aluminum?
1a. What is the percent yield for the reaction above if the experimental value was 210 g of Aluminum Oxide?
1b. How much of the excess reactant was used? How much of the excess reactant remains?

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.

Based on its chemical properties, identify the position of each chemical family on the periodic table.

4. a 20-kg child is tossed up into the air by her parent. the child is 2 meters off the ground traveling 5 m/s. circle one: ke / gpe / both show your work for finding the values of each type of energy the object has: