A chemist pumps hydrogen gas (H2) from a tank into a reaction vessel containing 0.734 mol O2.
The gases react to form water. If all of the
available O2 reacts, how many moles of H2 are
used?
0 0.367 mol H2
0.734 mol H2
1.47 mol H2

B? i feel like this is a trick  

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.

Ionly know number one that’s a galaxy

You can just look up the questions individually and get the answers