Because helium is lighter then the oxygen .and due to this helium gass carrier go upward easily .
Answer:
B and C is your answer
Explanation:
Hope I helped, Sorry if I'm wrong
A, B, and D. You already answered the first one, so I wouldn't think this would be too hard
:)
Atomic number for bromine is 35
Hey there!
Molar mass N2 = 28.01 g/mol
Therefore:
28.01 g N2 -------------- 6.02*10²² molecules N2
( mass N2 ?? ) ----------- 25,000 molecules N2
mass N2 = ( 25,000 * 28.01 ) / ( 6.02*10²³ )
mass N2 = 700250 / 6.02*10²³
mass N2 = 1.163*10⁻¹⁸ g
Hope that helps!