Question

Find the relative formula mass of $CaS{O}_4$?

• A. $146$
• B. $156$
• C. $136$
• D. $166$

Answer 1

The correct option is C $136$

The relative atomic mass of $Ca=40$
The relative atomic mass of $S=32$
The relative atomic mass of $O=16$
So, the relative molecular mass of $CaS{O}_4=40+32+16\times 4=136$