How much aluminum and sulfuric acid do you need to get 10 grams of hydrogen?

Given:
m (H2) = 10 g

To find:
m (Al) -?
m (H2SO4) -?

Solution:
1) Write the equation of a chemical reaction:
2Al + 3H2SO4 = Al2 (SO4) 3 + 3H2 ↑;
2) Using the periodic system of D.I.Mendeleev, calculate the molar masses of H2, Al and H2SO4, which will be numerically equal to the molecular weights:
Mr (H2) = Ar (H) * 2 = 1 * 2 = 2 g / mol;
Mr (Al) = Ar (Al) = 27 g / mol;
Mr (H2SO4) = Ar (H) * 2 + Ar (S) + Ar (O) * 4 = 1 * 2 + 32 + 16 * 4 = 98 g / mol;
3) Calculate the amount of substance H2:
n (H2) = m (H2) / Mr (H2) = 10/2 = 5 mol;
4) Calculate the amount of substance Al and H2SO4 (taking into account the coefficients in the reaction equation):
n (Al) = n (H2) * 2/3 = 5 * 2/3 = 3.3 mol;
n (H2SO4) = n (H2) = 5 mol;
5) Calculate the mass of Al and H2SO4:
m (Al) = n (Al) * Mr (Al) = 3.3 * 27 = 89.1 g;
m (H2SO4) = n (H2SO4) * Mr (H2SO4) = 5 * 98 = 490 g.

Answer: The mass of Al is 89.1 g; H2SO4 – 490 g.