Which of the following solutions demonstrates a chemical change?

What is the molar mass of potassium nitrate, kno3

Which ocean zone has the most abundant primary producer and why a) the abyssopelagic zone ,du to the absence of light and cold water temperatureb) the bathypelagic zone, due to the absence of light and cold water temperaturec) the mesopelagic zone ,due to uts high light availability and warm water temperature d) the epipelagic zone,due to its high light availability and warm water temperature

What is the molar mass of a gas that has density of 2.054 g/l