Which of the following sets of oxidation numbers is not correct? kmno4 : k +2, mn +6, o -2 nacho2 : na +1, c +2, h +1, o -2 zn(oh)2 : zn +2, o -2, h +1 scl2 : s +2, cl -1

A4.86 g piece of metal was placed in a graduated cylinder containing 15.5 ml of water. the water level rose to 17.3 ml. what is the density of the metal. i need the steps of how to solve it to so i can use a formula to work out other problems.