Question

Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrogen gas are formed when 48.7 g of sodium are added to water?. 2Na + 2H2O --> 2NaOH + H2. . Show your work.

Answer 1

Answer: 1.06 moles of molecules = 6.38x10²³ molecules


Explanation:


1) Balanced chemical equation:


2Na + 2H₂O -> 2NaOH + H₂


2) Mole ratios:


2 mol Na : 2 mol H₂O : 2 mol NaOH : 1 mol H₂


3) Convert 48.7 g of sodium to moles:


number of moles = mass in grams / molar mass


molar mass of Na = atomic mass = 23.0 g/mol


number of moles = 48.7g / 23.0 g/mol = 2.12 moles of Na

4) Proportion:


2moles Na/1mol H₂ = 2.12 moles Na / x


x = 2.12 moles Na * 1 mol H₂ / 2 moles Na = 1.06 moles H₂.


5) If you want to convert that to number of molecules you have to multiply by Avogadro's number: 6.022 x 10^²³


1.06 mol x 6.022x10^²³ molecules/mol = 6.38x10²³ molecules