A student investigated the reaction between zinc granules and dilute sulfuric acid. The equation for the reaction is:
Zn(s)+H2SO4(aq)→ZnSO4(aq)+H2(g) \text{Zn}(\text{s}) + \text{H}_2\text{SO}_4(\text{aq}) \rightarrow \text{ZnSO}_4(\text{aq}) + \text{H}_2(\text{g}) Zn(s)+H2SO4(aq)→ZnSO4(aq)+H2(g)The student used a conical flask connected via a delivery tube to a gas syringe. They added 40 cm340\text{ cm}^340 cm3 of dilute sulfuric acid to a chosen mass of zinc granules, quickly inserted the rubber stopper, and recorded the total volume of gas collected after the reaction had completely finished. They repeated this procedure for several different masses of zinc.
The table below shows the volume of gas collected in four trials using a mass of 1.5 g1.5\text{ g}1.5 g of zinc granules:
| Trial | Volume of gas produced (cm3\text{cm}^3cm3) |
|---|---|
| 1 | 48 |
| 2 | 47 |
| 3 | 12 |
| 4 | 49 |
Answer the following questions:
Identify the gas produced and collected in this investigation.
What was the independent variable in this investigation?
Give one control variable that must be kept constant to ensure a fair test.
Which trial gave an anomalous result? Calculate the mean volume of gas produced using only the non-anomalous trials (give your answer to 1 decimal place).
Suggest one practical error that could explain this anomalous result.