Molar mass helium gas :
He = 4.0 g/mol
number of moles: 3.75 / 4.0 => 0.9375 moles
1 mole ------ 22.4 ( at STP)
0.9375 ------ ?
volume = 0.9375 x 22.4 / 1
Volume = 21 / 1
Volume = 21 L
hope this helps!
<span>The correct answer is electron-cloud model. This model states that electrons don't go around in an eliptical way but rather completely erratically and uncontrolably and this is why it can't be known where they are or how they will behave. They form sort of like a cloud of many electrons that move erratically so you have to check it to see where it is.</span>
Answer:

Explanation:
mass of Fe = 55.85 g
Molar mass of Fe = 55.85 g/mol
<u>Moles of Fe = 55.85 / 55.85 = 1</u>
mass of Cl = 106.5 g
Molar mass of Cl = 35.5 g/mol
Moles of Cl = 106.5 / 35.5 = 3
Taking the simplest ratio for Fe and Cl as:
1 : 3
The empirical formula is = 
Answer:
in acetic acid ,there are 4 hydrogen atoms
Explanation:
C H 3 C O O H