When Copper is heated with Conc.HNO3, it produces-
Redox reactions:
Reaction of Copper with Conc.HNO3:
Cu(s)Copper+4HNO3aqNitricacid→Cu(NO3)2aqCupricnitrate+2NO2gNitrogendioxide+2H2OlWater
When copper powder is heated, it gets coated with