A scientist needs to use 4 moles of hydrogen and 2 moles of oxygen in order to make 2 moles of water. Using the molar amounts of hydrogen and oxygen, calculate the mass in grams of the samples of hydrogen and oxygen. Predict what the mass of the water (combined hydrogen and oxygen would be).

Henry moseley used x-ray experiments to determine the atomic number of elements. how did his discovery contribute to the development of the periodic table? a.it confirmed that elements should be arranged in strict order of increasing atomic mass. b.it led to elements with similar atomic numbers being grouped together. c.it allowed the elements to be placed in strict order of increasing atomic number. d.it showed that the way mendeleev grouped elements together was completely wrong.