Which of the following is a physical property flammability, heat of combustion, solubility, toxicity

As a part of an experiment a student burns propane to produce carbon dioxide and water she remembers that she must follow the law conservation of matter when writing a balanced chemical equation which of these equation adheres to the law of conservation of matter

Concerning the 10.0 ml of 0.50 m nacl to 100 ml of solution: when a solution is diluted, does it change the number of moles dissolved?

1) this is the structure in the cell nucleus that houses a cell's genetic information