m瓶=0.1kg,m瓶+m水=0.4m水=0.4-0.1=0.3kg=300gv水=m水/ρ=300/1=300cm^3m水1=m总-(m瓶+m金)=0.9-0.8=0.1kg=100gv水1=m水/ρ=100/1=100cm^3所以v金=v水-v水1=300-100=200cm^3m金=0.8-m瓶=0.8-0.1=0.7kg=700g所以ρ金=...