At 25 °c, what is the hydroxide ion concentration, [oh–], in an aqueous solution with a hydrogen ion concentration of [h ] = 4.2 × 10–9 m?

[oh-] = m

Which best describes why nh4+ can form an ionic bond with cl-?

What energy conversion occurs when a sling shot is used to shoot a rock across the room? (2 points) question 2 options: 1) stored mechanical energy is converted to mechanical energy. 2) stored mechanical energy is converted to radiant energy. 3) gravitational energy is converted to radiant energy. 4) gravitational energy is converted to mechanical energy.

4al + 3o2 → 2al2o3 what does the "3" in front of o2 stand for? a) it indicates that there are 5 oxygen atoms after you add the coefficient and the subscript. b) it indicates that that there are are total of 6 oxygen atoms all bonded together as a single molecule. c) it indicates that there are 3 oxygen molecules chemically bonded to each other in the reaction. d) it indicates that there are 3 separate oxygen molecules in the reaction.