When a powdered substance is added to water and dissolves, does the substance under go a chemical or a physical change ? How could you get the substance back ?

Compare and contrast physical changes with chemical changes.

Percent ionization for a weak acid (ha) is determined by the following formula: percent ionization=[ha] ionized[ha] initial×100%for strong acids, ionization is nearly complete (100%) at most concentrations. however, for weak acids, the percent ionization changes significantly with concentration. the more diluted the acid is, the greater percent ionization.a certain weak acid, ha, has a ka value of 9.4×10? 7.part acalculate the percent ionization of ha in a 0.10 m solution.part bcalculate the percent ionization of ha in a 0.010 m solution

Achemical reaction is done in the setup shown , resulting in a change of mass. what will happen if the same reaction is done in a sealed container that is placed on the electronic balance?