What would be and independent variable

What is the approximate vapor pressure when the gas condenses at 70 degrees celsius

At stp, which substance is the best conductor of electricity? a. nitrogen b. neon c. sulfur d. silver

A4.86 g piece of metal was placed in a graduated cylinder containing 15.5 ml of water. the water level rose to 17.3 ml. what is the density of the metal. i need the steps of how to solve it to so i can use a formula to work out other problems.