A flask contains helium and nitrogen gases. The partial pressures of each are
77 mm Hg and 87 mm Hg, respectively.
What is the total pressure in the flask in
mm Hg?

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope