Please help I'm so confused!

Question

Find the molar mass of PCl3? 

Answer 1

to find the molar mass of the compound you want to add together the atomic masses of all the atoms in its chemical formula. for this one that means taking

1*P + 3*Cl

=1(30.97) + 3(35.45)

=30.97 + 106.35

=137.32

meaning that the molar mass of PCL_3 is 137.32 g/mol

Answer 2

The molar mass of an element or compound is equal to the atomic mass of the element or compound except that is measured in grams. For example, an atom of helium has a mass of 4 amu. Therefore one mole of helium would have a mass of 4 grams.

 

Phosphorous has an atomic mass of 31 amu. Chlorine has an atomic mass of 35 amu. Therefore, the atomic mass of PCl₃ is 31 + 3*35 = 136 amu. Therefore, one mole of PCl₃ has a mass of 136 grams.