Table 1 shows a food-science investigation in which ethanol is oxidised to make ethanoic acid. The reaction is carried out in sealed bottles. For each bottl...
Question 1 Report
Table 1 shows a food-science investigation in which ethanol is oxidised to make ethanoic acid. The reaction is carried out in sealed bottles. For each bottle, the mass of oxygen used is found from the decrease in the oxygen reservoir.
| Bottle | Mass of ethanol / g | Mass of oxygen used / g | Mass of products / g |
|---|---|---|---|
| A | 2.30 | 2.40 | 4.70 |
| B | 3.45 | 3.60 | ? |
| C | 4.60 | 4.80 | 9.40 |
(a) Complete the missing mass of products for bottle B. [1]
(b) Use Table 1 to state the mass of reactants in bottle C. [1]
(c) Explain why bottle B has the product mass you calculated. [2]
(d) Name the element supplied by oxygen that becomes part of the products. [1]
A camping company tests a small fuel cell before fitting it into an emergency radio. Fig. 1 shows hydrogen and oxygen entering the cell and liquid water leaving. The company records the mass of each substance in a sealed collection box.
(a) Write the balanced symbol equation for the reaction in the fuel cell. [2]
(b) Use the equation to state how many moles of water form from 3 mol of oxygen. [1]
(c) Explain why the total mass of hydrogen and oxygen equals the mass of water formed when the cell is sealed. [2]
Answer Details
Ethanol oxidation
- \[3.45\text{ g}+3.60\text{ g}=7.05\text{ g}\]
Bottle B produces 7.05 g of products. [1] - The reactant mass in bottle C is 9.40 g. [1]
- Bottle B is sealed, and ethanol and oxygen are its reactants. Their atoms are rearranged into products, so the total mass of products equals the total mass of reactants. [2]
- The element supplied by oxygen is oxygen. [1]
Fuel cell
- \[2\mathrm{H_2}+\mathrm{O_2}\rightarrow2\mathrm{H_2O}\] [2]
- The equation shows 1 mol of \(\mathrm{O_2}\) makes 2 mol of \(\mathrm{H_2O}\). Therefore 3 mol of \(\mathrm{O_2}\) makes 6 mol of water. [1]
- Atoms are not created or destroyed. They are rearranged into water molecules, and all substances remain in the sealed collection box, so reactant and product masses are equal. [2]
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