Question

John placed 10 moles of sulphur molecules (S₈) and 5 moles of glucose (C₆H₁₂O₆) in the two different pans of a physical balance. Find which pan of the balance would be heavier, support your answer with calculations. 

(Atomic mass: O = 16 u, C = 12 u, H = 1 u, S = 32 u)

Answer 1

Molecular mass of sulphur molecules (S₈) 

= 32 × 8 = 256 gm 

Molecular mass of glucose (C₆H₁₂O₆) 

=(6 × 12) +( 1 × 12) +( 6 × 16) 

= 72 + 12 + 96=180 

Weight of 10 moles of S8 =10 × 256 = 2560 

Weight of 5 moles of glucose = 5 × 180 = 900 

Therefore, 10 moles of sulphur would weigh more.