Determine The Effect Of Each Of The Following Errors

Determine The Effect Each Of Following Errors Would Have On Your De

Evaluate the impact of specific errors during the process of analyzing a mixture of substances, focusing on how each mistake would affect the calculated percentages of each component. Discuss whether each error would lead to overestimation, underestimation, or no change in the determined quantities, providing clear explanations. The errors include washing residues with tap water instead of deionized water, not washing the residue from filtration, and spattering during heating. Additionally, perform a calculation to find the percentages of sodium chloride and sand in a mixture based on experimental data, and explain why their percentages may not sum to 100%. Finally, explain the reasoning behind covering the evaporating dish with a watch glass during evaporation but not during sublimation.

Paper For Above instruction

In the process of qualitative and quantitative analysis of mixtures in chemistry, precise procedures and techniques are essential for accurate results. Errors during experimental procedures can significantly distort the calculated component percentages, leading to misleading conclusions. This discussion explores the specific effects of three such errors, analyzes a calculation involving separation efficiency, and considers procedural choices during evaporation and sublimation to highlight their implications on experimental accuracy.

Impact of Errors on Determination of Mixture Components

The first error involves washing the residue with tap water instead of deionized water. This error can influence the accuracy of the determination of substances like ammonium chloride, salt, and sand. Tap water contains dissolved minerals and impurities which can adhere to the residue, potentially causing either a loss or contamination. For soluble components such as ammonium chloride and salt, washing with tap water might lead to partial dissolution or retention of impurities, causing the residual amount to be underestimated or overestimated. Specifically, if impurities are retained or soluble impurities are added, the measured amount of each component could be inaccurately high or low. Typically, washing with tap water could lead to an overestimation in the amount of insoluble substances, such as sand, and an underestimation of soluble substances if they partially dissolve during washing, thus skewing the results.

The second error pertains to failing to wash the residue from filtration. Proper washing removes any unreacted soluble substances or soluble impurities adhering to the solid residue. If not washed, soluble impurities, such as ammonium chloride and salt, may remain on the residue, leading to an overestimation of the amount of the insoluble component like sand. For soluble substances like ammonium chloride and salt, not washing will cause the measured weight to include residual soluble impurities, resulting in inflated values for those substances, or overestimating their percentages in the mixture.

The third error involves spattering during the initial heating of the mixture. Spattering can cause some of the material to be lost or distributed unevenly, affecting the amounts recovered. In case of ammonium chloride, spattering during heating can lead to the loss of volatile components, resulting in a lower measured residue, thus causing an underestimation of ammonium chloride content. For salt and sand, which are less volatile, the spattering may or may not significantly impact their measured amounts, but loss of volatile substances is more common with ammonium compounds during heating.

Calculation of Percentages in a Mixture of Sodium Chloride and Sand

Given a total mixture weight of 2.1035 g, where 1.7035 g of sodium chloride and 0.2904 g of sand were isolated, the percentage of each component can be calculated as follows:

• Percentage of sodium chloride = (mass of sodium chloride / total mixture mass) × 100 = (1.7035 g / 2.1035 g) × 100 ≈ 80.92%
• Percentage of sand = (mass of sand / total mixture mass) × 100 = (0.2904 g / 2.1035 g) × 100 ≈ 13.80%

Interestingly, these percentages do not sum to 100%, indicating that some of the original mixture was either lost during the separation process or other components or impurities were present. The sum of approximately 94.72% suggests an incomplete recovery or measurement inaccuracies, such as spattering, residual moisture, or experimental loss. Alternatively, the mixture might contain impurities or moisture not accounted for, affecting the total weight.

Reason for Covering During Evaporation but Not During Sublimation

Covering the evaporating dish with a watch glass during evaporation serves to minimize the loss of solvent through splattering and to prevent dust or airborne particles from contaminating the residue. It creates a controlled environment that promotes even evaporation and protects the sample from external contaminants. In contrast, during sublimation, the sample is heated to directly transition from solid to gas without intermediate liquid phase, and covering may impede the sublimation process or interfere with the escape of vapors. Additionally, sublimation often requires the vapor to escape freely and be condensed elsewhere, so covering the dish could trap vapors or hinder the process's efficiency.

Therefore, the watch glass covers to control evaporation and prevent contamination during liquid evaporation, but remain removed during sublimation to allow unobstructed vapor transfer and efficient collection of sublimed material.

Conclusion

Experimental errors such as using tap water instead of deionized water, neglecting to wash residues, or spattering during heating can significantly affect the accuracy of component percentage determinations in a mixture. Understanding these effects is crucial for designing robust procedures and interpreting results accurately. Calculations demonstrate the importance of precise measurement and account for potential losses or impurities. Procedural choices, like covering during evaporation but not sublimation, are based on optimizing the process efficiency and minimizing contamination or procedural interference under specific conditions.

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