Describe how would accurately prepare one litre of 150 ppm using copper

Answer 1

You can't make 150 ppm Cu. You can make 150 ppm Cu^2+
1 ppm = 1 mg/L.
150 ppm = 150 mg/L. So weigh 150 mg Cu, dissolve in a little HNO3, make to the mark in a 1 L volumetric flask with DI water, mix thoroughly, stopper, bingo.