Balance this equation and show work. brainliest zn + o2 → zn2+ + o2-

Since there are two oxygen on the left, you need two add 2 to the right oxygen
Zn + O₂ -> Zn²⁺ + 2O²⁻

The density of water is 1 g/cm cubed and in order for the pebble to sink its density has to be greater than the density of water and in order for the twig to float its density has to be less than the density of water