Error:
Cu2S %2B FeS2 %2B HNO3 %3D CuSO4 %2B NO %2B Fe2%28SO4%293 %2B H2O
^Unexpected character ('%')Cu2S %2B FeS2 %2B HNO3 %3D CuSO4 %2B NO %2B Fe2%28SO4%293 %2B H2O
^Unexpected character ('%')