A teacher wants to prepare a 0.010 ppm solution of arsenic pentoxide in the laboratory for caLiBrating a water quality testing system. If the teacher uses 500.0 ml of water (which has a mass of 500.0 g), What mass of arsenic pentoxide should the teacher mix to get the required solution?
1) 2.0 * 10⁻¹¹ g
2) 2.0 * 10⁻⁵ g
3) 5.0 * 10⁻⁶ g
4) 5.0 * 10⁻² g
