magnesium reacts with sulphuric acid according to the equation:

Question

Mg3 + H2SO4=MgSO4 + H2
a 250cubic centimetre aqueous solution containing 9.8g of sulphuric acid is added to 6g magnesium
a. show that the magnesium is present in excess
Does it have something to do with the unbalanced equation
b. calculate the mass of magnesium sulphate formed
c. calculate the mass of hydrogen gas measured at standard room temperature that was formed in the reaction

Answer 1

Where does the 3 from Mg3 come from. The equation is
Mg + H2SO4 ==> MgSO4 + H2

a. mols Mg = grams/atomic mass = ? about 0.2
mols H2SO4 = g/molar mass = ? about 0.1
Since 1 mols Mg reacts with 1 mol H2SO4 then 0.1 mols H2SO4 will use up 0,1 mol Mg and have some left over.

b. 0.1 mol H2SO4 will form 0.1 mol MgSO4. g MgSO4 = mols MgSO4 x mol mass MgSO4.

c. done the same way as part b.
Post your work if you get stuck.