mole conversions

Question

so i have the answers but dont know how to do the work to prove how I got the answers. can anybody help?

1)     CO2 - 44.01 g/mol

2)     SiBr4 - 343.65 g/mol

3)     fluorine - 18.998403 g/mol

4)     ammonium chloride - 53.491 g/mol

5)     KMnO4 - 158.034 g/mol

6)     Ba(OH)2 - 171.34 g/mol

7)     iron (III) nitrate - 242.86 g/mol

Answer 1

I find that not quite all of your answers are correct.

1) CO₂ = 12.01 + 2•15.999 = 44.01g

2) SiBr₄ = 28.085 + 4•79.904 = 347.70g - note

3) "Flourine" usually means F₂ gas = 2•18.998 = 37.996g - note

4) NH₄Cl = 14.007 + 4•1.008 + 35.45 = 53.49g

5) KMnO₄ = 39.098 + 54.938 + 4•15.999 = 158.03g

6) Ba(OH)₂ = 137.33 = 2•(15.999 + 1.008) = 171.34g

7) Fe(NO₃)₃ = 55.845 + 3•14.007 + 9•15.999 = 241.86g - note difference of 1g