Validity of the experiment:
Our experimental procedure tested the hypothesis and found the concentration of sulfate ions in the fertilizer. Thus it appears to be valid. However this meant that; we assume each step of the procedure was perfect e.g. the entire sulfate was precipitated and accounted for, there were no material losses, only the sulfate precipitated with the barium and there were no other interfering substances etc. but this is not possible because
• Some BaSO4 would be lost in mechanical transfer.
• Not all of the BaSO4 would form large crystals and some will be lost while filtering
• Many impurities could have formed on the surface of the precipitate and thus increased its mass. The groups who used more than 2g of fertilizer found that there results were a lot more than the actual value.
• Some BaSO4 could adhere to the walls of the beaker
So the experimental procedure was invalid because there are high chances of errors.
Our experimental procedure tested the hypothesis and found the concentration of sulfate ions in the fertilizer. Thus it appears to be valid. However this meant that; we assume each step of the procedure was perfect e.g. the entire sulfate was precipitated and accounted for, there were no material losses, only the sulfate precipitated with the barium and there were no other interfering substances etc. but this is not possible because
• Some BaSO4 would be lost in mechanical transfer.
• Not all of the BaSO4 would form large crystals and some will be lost while filtering
• Many impurities could have formed on the surface of the precipitate and thus increased its mass. The groups who used more than 2g of fertilizer found that there results were a lot more than the actual value.
• Some BaSO4 could adhere to the walls of the beaker
So the experimental procedure was invalid because there are high chances of errors.
