Question

If 0.5 mole of sodium burns in oxygen, sodium hydroxide is formed.
Write down a balanced chemical equation for the reaction.
Calculate the mass of sodium that reacts.
Determine the number of moles of sodium ions formed.

Answer 1

The general equation for the reaction is;

$Na+O\to Na_2O$

Mass$=$ Moles$\times$ Molar mass.

Moles$=0.5M$

Molar mass of $Na_2O=54.989=54.99$

From the formula;

$\therefore$ Mass$=$ $0.5\times 54.989$ $= 27.49g$

The mass of $Na$ which reacts$=27.49g$

Number of moles $=$ $Mass Of Substance\over Mass Of One Mole$

Number of moles of $Na=$ $27.49\over 54.989$ $=0.499mol$

The number of Moles of Sodium ions formed $=0.49 moles$