Which statement about a physical and chemical change is true? Question 5 options:

If NO change in color is visible in a process, it must be a chemical change

if NO change in state of matter occurs in a process, it must be a physical change

A change in state of matter always indicates a chemical change

A change in color often occurs during a chemical change

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]