Jack tries to place magnets on the door of his refrigerator. he observes that the magnets don't stick. he guesses that the door of the refrigerator id made of non magnetic substance. what stage of scientific investigation does his guess represent?

When a chemist collects hydrogen gas over water, she ends up with a mixture of hydrogen and water vapor in her collecting bottle if the pressure in the collecting bottle is 97.1 kilopascals and the vapor pressure of the water is 3 2 kilopascals, what is the partial pressure of the hydrogen?