If precipitation of BaSO4 is incomplete due to inadequate heating or insufficient time what will happen to the sulfate percent error determination? And why?
Just below, I responded to a similar question by Matt suggesting this is a poor question. The only correct answer I think is that the percent error will increase and surely that is too simple an answer. The error will increase, meaning it will be an error mor than perfect results, because if some of the BaSO4 is not recovered then not all of the sulfate was recovered and that results in an error. Surely that is obvious from the beginning.
If precipitation of BaSO4 is incomplete due to inadequate heating or insufficient time, it will result in a higher percent error in the sulfate determination.
To understand why, let's break it down step by step:
1. The percent error in the sulfate determination is calculated by comparing the experimental value of sulfate with the expected or theoretical value. The formula for percent error is:
Percent Error = (|Experimental Value - Theoretical Value| / Theoretical Value) * 100%
2. To determine the amount of sulfate present, a precipitation reaction is typically used, where Ba2+ ions combine with SO42- ions to form BaSO4, which is a solid and can be easily separated from the solution.
3. Incomplete precipitation occurs when not all the sulfate ions (SO42-) present in the sample are converted into BaSO4 precipitate. This can happen due to inadequate heating or insufficient time for the reaction to reach completion.
4. If incomplete precipitation occurs, the experimental value of sulfate would be lower than the theoretical value because not all the sulfate ions are being accounted for in the precipitate.
5. When calculating the percent error, the experimental value is subtracted from the theoretical value. Since the experimental value is lower than it should be, the difference between the experimental and theoretical values will be larger, resulting in a higher percent error.
In summary, inadequate heating or insufficient time leading to incomplete precipitation of BaSO4 will cause a higher percent error in the sulfate determination because the experimental value will be lower than the theoretical value.