everything part has different weights. i cant give you a exact amount for anything
ill give you a rough idea though
CPU=100-200g
motherboard=1-4 pounds depending on size, accessories, and the motherboard itself
psu=5-10 pounds depending on size. 5 for 550w or under. 10+ for 800-1000w
case=9-50 pounds depending on the size and material. 9 being cheapass budget case. 50 being cosmos 2 from CM
ram=100g tops
drive=2 pounds shipped
cords=50g a piece