How many moles of HCl need to be added to 200.0 mL of a 0.200 M solution of NaF to make a buffer with a pH of 2.80? (Ka for HF is 6.8 × 10⁻⁴)

Which of your 24 wells had indications that a chemical reaction occurred? how were you able to tell that a chemical reaction occurred? which of your 24 wells had indications that a physical reaction occurred? how were you able to tell that a physical reaction occurred? report on both mixing and evaporation. make a general statement about whether your hypotheses were validated or rejected. must your hypotheses be correct for this to be a successful laboratory?