What volume of 0.25 M HCl must be diluted to prepare 0.64 L of 3.5×10^-2 M HCl?

An observation that requires measurement is called quantitative observable or qualitative

Achemist has dissolved a certain substance in water. the chemist knows that more of the substance could be dissolved into the water before it stops dissolving. therefore

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?