While heating copper in the final step, the bright copper color changes to dull brown. will percent recovery be too high, too low, or unaffected? explain your answer

Copper is an element in the periodic table with the chemical symbol Cu and atomic number which is equal to 29. This is a metallic element that is soft, ductile, and malleable. Also, this has very high electrical and thermal conductivity. 

This metal, when freshly exposed is a reddish-orange color. The situation given above, it is described that copper has already reacted with oxygen, as described by the change of color. This means that the percent recovery of the metal will be less since portion of it has already reacted. 

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.

Answerchemical energy;