How could you avoid experimental bias?

Name the element in group 17, period 2. (periodic table)

Assuming complete dissociation of the solute, how many grams of kno3 must be added to 275 ml of water to produce a solution that freezes at -14.5 c? the freezing point for pure water is 0.0 c and k_f is equal to 1.86 c/m

Areaction in which products can react to re-form reactants is