The students want to collect data on how the average kinetic energy of the liquid water molecules in the ice baths changes during the experiment. Which statement best describes a change to the ice bath experiment that will help the students collect this data? A Measure the water height in each ice bath throughout the experiment and compare the initial and final water heights. B Measure the water volume in each ice bath throughout the experiment and compare the initial and final water volumes. C Measure the size of each piece of ice in each ice bath throughout the experiment and compare the initial and final sizes of each piece of ice. D Measure the water temperature in each ice bath throughout the experiment and compare the initial and final water temperatures.

C

Explanation:

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g