Calculation from Chemical Equations

Example 9.3.1:

Sodium combines with oxygen as follows:

\( \scriptsize 4Na_{(s)} \: + \: O_{2(g)} \: \rightarrow \: 2Na_2O_{(s)} \)

What is the mass of oxygen needed to burn 4.6 g of sodium?

(Na = 23, O = 16)

Solution:

From the Equation:

4 moles of Na reacts with 1 mole of O₂

Relative mass of 4Na = 4 × 23 = 92 g
Relative mass of O₂ = 2 × 16 = 32 g

92 g of Na reacts with 32 g of O₂

Let the mass of oxygen