Standard solutions of sodium hydroxide, NaOH, must be kept in airtight containers - VCE - SSCE Chemistry - Question 9 - 2016 - Paper 1

The balanced equation for the reaction is:

$2NaOH(aq) + H_2CO_3(aq) \rightarrow Na_2CO_3(aq) + 2H_2O(l)$

To calculate the amount of CO2 that enters the container, we can use the ideal gas law and the concentration of CO2 in the air:

1. Calculate the volume of air entering:

   $V_{air} = 10.00 L - 9.90 L = 0.10 L$

2. Using the concentration of CO2 in the air, calculate the amount of CO2 in moles:

   $n(CO_2) = 0.0400 \% \times V_{air}$

   $= 0.00040 \times 0.10\,L$

   $= 1.64 \times 10^{-4}\, mol$

Thus, the amount of CO2 that entered the container is approximately $1.64 \times 10^{-4}\, mol$.