If a student used an iron scoopula, instead of a plastic one, to add the unknown metal to the HCl solution, will it affect the calculated molar mass of the unknown metal? If so, how? Justify your answer with an explanation.
If the iron scoopula is clean, not oxidized, and is finely polished so that no unknown adheres to it I don't think it will make any difference. However, if there is rust on the iron scoopula and some of that falls into the HCl solution the results may be affected. You don't give the procedure so I don't know if the results will be high or low (or no change).
Using an iron scoopula instead of a plastic one to add the unknown metal to the HCl solution can potentially affect the calculated molar mass of the unknown metal. The reason for this is that iron is a metal itself, and it can react with the HCl solution to produce hydrogen gas. This reaction can lead to a loss of the unknown metal during the experiment, resulting in an inaccurate measurement of the molar mass.
When iron reacts with hydrochloric acid, the following chemical reaction takes place:
Fe + 2HCl -> FeCl2 + H2
In this reaction, iron (Fe) reacts with hydrochloric acid (HCl) to produce iron(II) chloride (FeCl2) and hydrogen gas (H2). The released hydrogen gas can escape into the atmosphere, leading to a loss of mass in the system and resulting in an incorrect measurement of the molar mass of the unknown metal.
To avoid this issue, it is important to use a non-reactive material, such as a plastic scoopula, when adding the unknown metal to the HCl solution. This ensures that the reaction occurs only between the unknown metal and the acid, without any interference from the scoopula material. By using the correct materials, accurate results can be obtained for the molar mass of the unknown metal.