Question

If we consider that 1/4 in place of 1/12 mass of a carbon atom to be the relative atomic mass unit, the mass of one mole of a substance will:

• A. Decrease thrice
• B. Increase twofold
• C. Increase thrice
• D. Be a function of the molecular mass of the substance

Answer 1

The correct option is A Decrease thrice

If the atomic mass unit changes to $\frac{1}{4}$ of a C-12 atom, then the new base unit (amu') would be:
$\frac{12}{4}=3$ amu.
This would mean that the new mass of C-12 would be:
$\frac{12}{3}=4$ amu'
Comparing the old and the new mass, the new mass decreases by 3 times.