Why does a mole of silicon weigh a different amount than a mole of carbon?

in the given question, the partial pressure is calculated by using the ideal gas equation, that is, pv = nrt

here, p is pressure, v is volume = 25 l, n is number of moles = 0.0104 moles, r is gas constant = -0.0821 l.atm / mol.k

t is temperature = 273 k

p = nrt / v

p = (0.0104 mol × 0.0821 l.atm / mol.k × 273 k) / 25 l

= 0.0093 atm

answer; talc and gypsum;

answer; the numbers of valence electrons in the acetic acid molecule (ch3co2h) is 24;

it's c (engineer's do their work with mechanical stuff not on any living being)