How many moles of helium are equivalent to 1.5 x 1023 atoms? Round to 2 places after the decimal.
Type in numerical answer. Do not include units for this answer.

Iknow #2 is d. i just need to know why

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.

How many grams of co(g) are there in 74.5 ml of the gas at 0.933 atm and 30o c?