What is the concentration if 20 grams of NaOH was dissolved in enough water to make a 250 mL NaOH solution?

If you add 5.00 ml of 0.100 m sodium hydroxide to 50.0 ml of acetate buffer that is 0.100 m in both acetic acid and sodium acetate, what is the ph of the resulting solution? acetic acid: ka = 1.8. x 10-5

Asample of sea water contains 6.28g of sodium chloride per litre of solution. how many milligrams of sodium chloride would be contained in 15.0ml of this solution?

Suppose you discovered a new element with 120 protons and 2 electrons in its outer level . i'm what group does this new element belong? what properties would you expect it to have