Find the mass of magnesium sulfate, which is formed by the interaction of sulfuric acid

Find the mass of magnesium sulfate, which is formed by the interaction of sulfuric acid with magnesium of 96 g, containing 25%.

Given:
W (impurities) = 25%
m (Mg) = 96 g
To find:
m (H2SO4) =?
Solution:
1) Let’s compose the equation of the chemical reaction
H2SO4 + Mg = MgSO4 + H2
2) Find the mass of pure magnesium for this we use the formulas:
W = (m substance: m solution) x 100%;
m substance = (W x m solution): 100%;
W of a pure solution = 100% – 25% = 75%;
m (Mg) = (96 g x 75%): 100% = 72 g.
3) We know the mass of magnesium, and let the mass of H2SO4 be x g.
Let’s find the molecular weight of magnesium.
M (Mg) = 24 g / mol
Find the molecular weight of MgSO4.
M (MgSO4) = 24 + 32 + 64 = 120 g / mol
4) 72 g: 24 g / mol = x g: 120 g / mol
x = (72 x 120): 24 = 360 g.
Answer: m (H2SO4) = 360 g.