What is the mass in grams of 4.03 x 10(23) H2 molecules at STP?

1 Answer
Dec 5, 2014

The asnwer is #1.34grams#.

One mole of diatomic hydrogen, #H_2#, has #6.022 * 10^23# #H_2# molecules, and weighs approximately #2grams#.

However, just by looking at the number of #H_2# molecules given, you can estimate that this amounts to less than #1# mole.

#4.03 * 10^23# molecules * (#1# mole)/(#6.022 * 10^23#molecules) = #0.67# moles of #H_2#.

Therefore, the mass is equal to

#0.67# moles * #2 g/(mol) = 1.34 grams# of #H_2#.