Final answer:
The mass of the final product will be too low if impurities present in a 'dirty' crucible are burned off during a chemical experiment, as this does not adhere to the Law of Conservation of Mass, leading to inaccurate results in gravimetric analysis or percent yield calculations.
Step-by-step explanation:
The question involves understanding how the presence of impurities affects the mass of the final product after a chemical experiment. When a crucible that is not fired and contains impurities is used, and those impurities are burned off during the experiment, the mass of the final product will be too low. This is because the initial mass recorded includes the mass of the impurities, and once they are burned off, they no longer contribute to the final mass.
According to the Law of Conservation of Mass, the total mass before and after a chemical reaction must be the same. If impurities are present at the start and not at the end, the mass of the product alone will be lower than the combined mass of the product and the impurities at the start. This could lead to an incorrect calculation of the percent yield, as yields greater than 100% are possible when impurities are in the final product, causing its mass to be greater than that of the pure product.
In gravimetric analysis, the mass of the sample before and after a change of state is critical for accurate results. The mass of precipitate filtered, dried, and weighed is used to calculate analyte concentration. Any change in mass due to impurities can lead to errors in the calculated concentration of the analyte.