How many valence electrons are there in the following atom?

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

What are transitions between a liquid and a solid called? identify which way they are transitioning

22. a flask containing 450 ml of 0.50 m h2so4 was accidentally knocked to the floor. how many grams of nahco, do you need to put on the spill to neutralize the acid according to the following equation: h2so4(aq)+2 nahcos(aq) na,so(aq) +2 h20()+2 co2(g) d) 38 g a) 2.3 g b) 9.5 g c) 19 g