If the experiment had been completed with no error, the percent recovery should have been no lower than 90%. In our case, the recovery was 69% which shows that some mistakes were made along the way. Several errors were made during the lab procedure that caused the copper to be lost in the end result. In reaction one, tap water could have been left in the bottom of the beaker when the Nitric acid was added which could have caused the reaction to be changed which could have caused less copper to be recovered.
And as in all experiments, the nitric acid and the copper wire could have not been measured as accurately as possible. In reaction two, the stirring rod could have had unknown substances from a previous experiment on it, because it was not cleaned before it was put into the copper sample. This could have allowed other matter to enter the solution. In reaction three we did not stir well enough before decanting the liquid.
We did not allot enough time for the precipitate to settle before decanting, which could have caused a significant amount of copper to be lost. In reaction five, the wire was to be shaken to dislodge the copper solid. When we shook the wire, it broke off from the piece we were using to hold it, which caused a direct loss of copper that could have been dislodged from the wire. Lastly, when we transferred the copper from the beaker to the watch glass to dry, we did not remove all of it, which caused for the percent recovery to be lower than 90%.
