1. If the unknown solid were not dried before analysis, would the calculated percent of KHP be too high or too low? Explain
If the unknown solid were not dried before analysis, the calculated percent of KHP would be too high. The reason for this is that KHP (potassium hydrogen phthalate) contains water molecules in its crystal structure. When the KHP is not dried, the water molecules present in the crystal will contribute to the overall mass of the solid.
During the analysis of KHP, a common technique used is to measure the mass of the solid before and after heating or drying it. This process is done to remove any water molecules from the solid. By heating or drying the solid, the water molecules are evaporated and removed, leaving behind only the anhydrous KHP.
If the unknown solid is not dried before analysis, the water molecules will still be present and will contribute to the mass obtained during the analysis. As a result, the calculated percent of KHP, which is determined by dividing the mass of KHP by the total mass of the sample, will be higher than it should be. This is because the presence of water molecules will falsely increase the mass of KHP in the sample, leading to an overestimation of the percentage.
To ensure accurate results, it is crucial to properly dry the unknown solid before analysis to remove any water molecules and obtain the correct mass of KHP.