1.What volume of carbon dioxide (CO2) will be produced if 2.90 moles of iron (Fe) is produced? [Note: In the Gizmo, it is assumed that all gases are at standard temperature and pressure, or STP.] Given unit: ___2.9 Answer unit: Solution:

2. What mass of iron (Fe) can be obtained from 3.80 g iron (III) oxide (Fe2O3) reacting with excess carbon monoxide (CO)?

Given unit: 3.8 Answer unit: Solution:

3.How many moles of iron (Fe) will be produced from 6.20 moles of carbon monoxide (CO) reacting with excess iron (III) oxide (Fe2O3)?

Given unit: 6.2 Answer unit: Solution:
4.How many molecules of carbon monoxide (CO) are needed to react with excess iron (III) oxide (Fe2O3) to produce 11.6 g of iron (Fe)?

Given unit: ___11.6 Answer unit: Solution:
Fe2O3 + 3CO 2Fe + 3CO2

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.

Using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 pb+2(aq) + 2cl -(aq). if the value of ksp was determined to be only 1.2 x 10-2: too much solid has dissolved. additional precipitate is forming. the solution is unsaturated. the ions are now combining to reduce their concentrations.

How is energy related to the change of state represented by the model? atoms gain energy as a solid changes to a liquid. atoms gain energy as a solid changes to a gas. atoms lose energy as a solid changes to a liquid. atoms lose energy as a solid changes to a gas.