Did you mean milliliters? if so your answer would still be 876 because they are equal. I don't think it is possible to convert millimeters and grams :)
A because a primary source is defined as a first hand account of an event .
The last two.
2C3H6(g)+9O2(g)-> 6CO2(g)+6H2O(g)
Fe2O3(s)+3CO(g)-> 2Fe(I)+3CO2(g)
Atomic <span>mass He = 4.002 u.m.a
4.002 g --------------- 6.02x10</span>²³ atoms
50 g ------------------ ? atoms
50 x ( 6.02x10²³) / 4.002
= 3.01x10²⁵ / 4.002
= 7.52x10²⁴ atoms of He