If not all the alum dissolves in the water before adding the Ba(NO3)2 solution, what effect will this have on the sulfate percent error determination?
percent error of what? %error alum? %error mass BaSO4? etc.
If not all the alum dissolves in the water before adding the Ba(NO3)2 solution, it will have an effect on the sulfate percent error determination. When the Ba(NO3)2 solution is added, it reacts with the sulfate ions present in the alum to form a precipitate, which is then filtered and weighed to determine the sulfate content.
If there is undissolved alum in the mixture, the sulfate ions associated with this undissolved alum will not react with the Ba(NO3)2 solution. As a result, the measured weight of the precipitate (BaSO4) will be lower than expected since it only accounts for the sulfate ions that successfully reacted. This would lead to a lower measured sulfate content.
The percent error determination compares the measured value obtained in the experiment with the theoretical value. In this case, if there is undissolved alum, the measured value will underestimate the actual amount of sulfate present in the sample. Therefore, the percent error will be higher, indicating a larger deviation from the expected value.
To improve the accuracy of the sulfate percent error determination, it is important to ensure thorough mixing and dissolution of the alum in the water before adding the Ba(NO3)2 solution. This can be achieved by stirring the mixture and allowing sufficient time for the alum to dissolve completely. By ensuring complete dissolution, the impact of undissolved alum on the percent error determination can be minimized.