An ions have charge and it gains or loses electrons.
the answer is B because I jus did that
A . O2- because it is a negatively charged ion
In your choices, the best answer is the mass of the reactants and the mass of the products are no equal. The chemical equilibrium can take place in a close system and can not be affected by catalyst and is a reversible reaction. The best describe should be the concentration of reactants and products are constant.
A. The molecules of solids are close together and compact, liquids are spread out but not too far apart, and gas molecules are really far apart.
B. Increase in temperature causes pressure to go up. Decrease in temperature cause pressure to go down