Question

Solid sodium metal reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of of hydrogen are formed when 35 g of sodium are added to water?

Answer 1

Sodium reacts vigorously with water to form sodium hydroxide and hydrogen gas with production of heat.
 2Na (s) + 2H2O (l) = 2NaOH (aq) + H2 (g)
The mass of sodium contains 35 g ÷ 23 g = 1.522 moles.
Using the mole ratio of Sodium to hydrogen gas ( 1:2) we can get the moles of hydrogen produced , That is 1.522 moles ÷2 = 0.761 moles
From the Avogadros law ; one mole of a substance contains 6.02 × 10∧23 particles . Therefore,the number of molecules of hydrogen will be given by; 0.761 moles × 6.02 × 10∧23 = 4.581× 10∧23 molecules
Therefure 4.581 × 10∧ 23 molecules are formed.