It’s Calcium hope that helps!
The answer is powder because if it was a small crystal it the molecules are tightly compact same with the small cube but there less compact, powder is loose and more spread out and easier to mix so it would react the fastest
Arrhenius theory is a theory about acids and bases. It says that acids are those substances that produces hydrogen ions (H+) when in solution and bases are the substances that dissiociates and produces hydroxide ions (OH-). It was introduced by Svante Arrhenius.
Physical properties of matter
Standardized means that a specific amount EDTA is added to a specific volume of distilled water. Water hardness is determined by the the amount of a standard EDTA solution to change the color of the water from red to blue. For example if one added the correct amount of EDTA to twice the volume of distilled water the solution would be weak. Titration of the hard water would give a erroneous high result.