Why Couldn't Sara see anything when she first went into the exhibit at Lawrence Hall of Science?

One of the reactions in a blast furnace used to reduce iron is shown above. how many grams of fe2o3 are required to produce 15.5 g of fe if the reaction occurs in the presence of excess co? a.11.1 g b.22.1 g c.30.0 g d.44.2 g

Maria wants to determine which type of disinfectant kills the most bacteria. which of the following is the best way for maria to determine this? a. ask ten different companies that make disinfectants which type is best. b. put the same amount and species of bacteria on ten identical plates, and add ten different kinds of disinfectant to each plate. c. interview ten different people to determine which type of disinfectant they prefer. d. put the same amount and species of bacteria on ten identical plates, and add a different disinfectant to each plate.

8) a mixture of he, ne and ar has a pressure of 7.85 atm. if the ne has a mole fraction of 0.47 and 8) ar has a mole fraction of 0.23, what is the pressure of he? a) 4.2 atm b) 3.7 atm c) 5.5 atm d) 2.4 atm e) 1.8 atm