Final answer:
Deviations in experimental protocol, such as allowing fumes to escape, not adding water, spattering during evaporation, and incomplete evaporation of water, can impact the measured weight of magnesium oxide by causing either a loss of mass (in case of escaped fumes and spattering) or an increase in apparent mass (due to the presence of unevaporated water).
Step-by-step explanation:
When performing an experiment to measure the weight of magnesium oxide produced, any deviation from the procedure can impact the results:
- Fumes escaping from the crucible: If fumes are allowed to escape from the crucible, it likely means that magnesium oxide is being lost, potentially as magnesium and oxygen gas (MgO). This would result in a lower final weight of magnesium oxide.
- Water not added to the crucible: If water was not added, it does not directly affect the weight of the magnesium oxide, unless water was part of the intended procedure for reaction or cleaning.
- Spattering during water evaporation: If spattering occurred during the evaporation of water, some of the magnesium oxide may have been lost, also leading to a lower final weight.
- Water not completely removed by evaporation: If water was not completely removed, the final weight measured includes both magnesium oxide and the remaining water, causing the recorded weight to be higher than the true weight of magnesium oxide alone.
The law of conservation of mass indicates that the mass of products in a chemical reaction should equal the mass of the reactants if all substances are accounted for and no matter is allowed to escape.