Which veriable should he change, measure and control (temp of water, volume of water and mass of sodium chloride that dissolve )in a dissolving investigation

What is the density of the black hole

If i can still dissolve more sugar into the solution at a certain temperature what would i call that solution

Acompound has a molar mass of 92.02 grams/mole, and its percent composition is 30.4% nitrogen (n) and 69.6% oxygen (o). what is its molecular formula? a. n2o4 b. no2 c. n2o d. n4o2