Help me out here I don’t understand please :(, ppl srsly answer my questions a week later :/

The density of an unknown gas at 98°c and 740 mmhg is 2.50 g/l. what is the molar mass of the gas with work showed?

The famous scientist galileo galilei did several experiments with sloping planes, which he rolled metal balls down so that he could study motion. by changing the slope, he could study how the speed at which the ball rolled was affected. what was the independent variable in galileo's experiment? a. the speed of the ball b. the slope of the plane c. whether the ball moved d. what the ball was made of

Asolution is made by dissolving 2.3 moles of sodium chloride (nacl) in 0.155 kilograms of water. if the molal boiling point constant for water (kb) is 0.51 °c/m, what would be the boiling point of this solution? show all the steps taken to solve this problem.