Use the average atomic masses given inside the front cover of this book to calculate the mass in grams of
each of the following samples.
a. 0.251 mole of lithium
b. 1.51 moles of aluminum
C. 8.75 X 10-2 moles of lead
d. 125 moles of chromium
e. 4.25 X 10' moles of iron
f. 0.000105 mole of magnesium

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 effect does a decrease in temperature have on the overall rate of a chemical reaction? a decrease in temperature decreases . the reaction rate will

Which of the following represents the ester functional group? a. -coo- b. -cho c. -cooh d. c=o