Ihave a question on my chem homework. it's asking "how many molecules of n2o4 are in 76.3 g n2o4? the molar mass of n2o4 is 92.02 g/mol." i am really confused as to how to do this. ? ?

Apeak with a retention time of 407 s has a width at half-height (w1/2) of 7.6 s. a neighboring peak is eluted 17 s later with a w1/2 of 9.4 s. a compound that is known not to be retained was eluted in 2.5 s. the peaks are not baseline resolved. how many theoretical plates would be needed to achieve a resolution of 1.5?

Ascientist measures the speed of sound in a monatomic gas to be 449 m/s at 20∘c. what is the molar mass of this gas?

Which of the following units is not an official si unit