Answer:
28.11g
Step-by-step explanation:
Step 1:
Background understanding:
From Avogadro's hypothesis, 1 mole of any substance contains 6.02x10^23 atoms. This also indicates that 1 mole of helium (He) contains 6.02x10^23 atoms.
1 mole of He = 4g
Step 2:
Determination of the mass of He that contain 4.23x10^24 atoms. This is illustrated below:
4g of He contains 6.02x10^23 atoms.
Therefore Xg of He will contain 4.23x10^24 atoms i.e
Xg of He = (4x4.23x10^24)/6.02x10^23
Xg of He = 28.11g
Therefore, 28.11g of He contains 4.23x10^24 atoms