The crucible is handled with oily fingers after its mass measurement but before the 3 gram sample of the hydrated salt is measured. Subsequently, in part B.1, the oil from the fingers is burned off. Will the percent water in the hydrated salt be reported as being too high, too low, or unaffected? Explain.
i think its unaffected. but i don't know if I'm right, and I don't know how to exactly explain it.
To determine whether the percent water in the hydrated salt will be reported as too high, too low, or unaffected, we need to understand the process of measuring the percent water in the salt.
First, the crucible, which is used to hold the hydrated salt during heating, is handled with oily fingers after its mass measurement. This means there might be residual oil on the crucible's surface.
Next, a 3 gram sample of the hydrated salt is measured and placed inside the crucible. During heating in part B.1, the objective is to remove the water content from the salt.
Now, let's analyze the effects of the oily residue on the percent water measurement:
1. Too High: If the oil residue on the crucible is not adequately burnt off before heating the sample, it may partially combust and contribute additional weight to the crucible. This excess weight would result in an erroneously higher mass measurement in the final analysis, leading to a higher reported percent water content.
2. Too Low: On the other hand, if the oil residue is entirely burned off during the heating process, it would not directly affect the measured mass of the hydrated salt. Consequently, the reported percent water content would not be affected or biased towards a lower value.
3. Unaffected: In the scenario where the oil residue is fully burned off, the measured mass of the hydrated salt would accurately represent its content, and the reported percent water would be unaffected.
Based on this analysis, if the oil residue is completely burned off during part B.1, which is the usual expectation, the percent water in the hydrated salt should be reported as unaffected.