A food manufacturer checks the amount of carbon dioxide made when sodium carbonate is used to clean a pipe. Table 1 gives the masses measured in a closed ve...
Question 1 Report
A food manufacturer checks the amount of carbon dioxide made when sodium carbonate is used to clean a pipe. Table 1 gives the masses measured in a closed vessel after sodium carbonate solution reacts with excess hydrochloric acid. The equation is Na2CO3 + 2HCl → 2NaCl + H2O + CO2.
| Mass of sodium carbonate / g | Mass of hydrochloric acid that reacts / g | Mass of carbon dioxide / g | Mass of sodium chloride and water / g |
|---|---|---|---|
| 5.30 | 7.30 | 2.20 | ? |
(a) Use conservation of mass to calculate the missing mass in Table 1. [2]
(b) Give the number of sodium atoms on the left side of the equation. [1]
(c) Describe why the equation is balanced. [2]
(d) Draw a circle around the reactant that is an acid. [1]
Answer Details
(a) First calculate the total mass of reactants:
\[5.30\text{ g}+7.30\text{ g}=12.60\text{ g}\]
Then subtract the mass of carbon dioxide:
\[12.60\text{ g}-2.20\text{ g}=10.40\text{ g}\]
The mass of sodium chloride and water is 10.40 g. [2]
(b) There are 2 sodium atoms on the left side, in \(\text{Na}_2\text{CO}_3\). [1]
(c) The equation is balanced because each element has the same number of atoms on both sides of the equation. Therefore atoms, and hence mass, are conserved in the reaction. [2]
(d) The reactant that is an acid is HCl, hydrochloric acid. [1]
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