A rock has a mass of 90.0g and a volume of 28.3cm3. What is the density of the rock?

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

How do you lengthen a pattern piece? (family and consumer science, sewing)

Insoluble sulfide compounds are generally black in color. which of the following combinations could yield a black precipitate? check all that apply. na2s(aq)+kcl(aq) li2s(aq)+pb(no3)2(aq) pb(clo3)2(aq)+nano3(aq) agno3(aq)+kcl(aq) k2s(aq)+sn(no3)4(aq)