The blue color of copper (ii) sulfate will change to green, yellow, orange ,red and then a dark red or brown.
Glucose is a reducing sugar; reducing sugars are sugar that forms an aldehyde or ketone in the presence of an alkaline solution. Reducing sugars reduce the blue copper sulfate from the Benedict's solution to a red brown copper sulfide; which is seen as the precipitate and is responsible for the color change.
The answer is number 4 or the exchange of energy with the surroundings. Calorimetry is a measurement of energy that is formed or absorbed in a certain process. The calorimeter is the instrument used in order to measure the energy. It is recommended that a calorimeter should be a closed system so as to measure precisely the energy and avoid or lessen the exchange of energy with the surroundings. Thus, comparing an open ceramic mug and an insulated mug with a lid, the greatest difference is the energy lost to the surroundings.
