<span>The number of moles of Cl- ions needed to combine completely with 0.25 mole of Mg+2 ions is:
0.50.</span>
The usual units of density are g/cm.
You may have also seen g/mL used for density. Keep in mind that 1 cm = 1 mL.
I think number one is c not sure or not number 2 is C AND NUMBER 3 IS 1 Go with sliding friction number 2 go with rolling friction number 3 is static friction and 4 is force