Relative atomic mass Imat 2022 Q 46

Practice Question Solving
1

Hi! The correct answer is A. Can someone please explain this?

A metal oxide, MO, reacts with sulfuric acid according to the following equation:

MO + H2SO4 → MSO4 + H2O

2.8 g of the metal oxide requires 25 mL of 2.0 mol L–1 sulfuric acid for complete reaction.

What is the relative atomic mass (Ar) of the metal?
[Ar value: O = 16]

A 40
B 24
C 56
D 96
E 112

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2

Hi,

0.025 L* 2 mol/L= 0.05 moles
from the reaction, we can conclude that 1 mole of MO will react with 1 mole of H2SO4. hence,
0.05 moles= 2.8 g/ atomic mass
atomic mass= 2.8/0.05
=56
Since the atomic mass of O is 16,
M= 56-16
=40

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