2 atoms of hydrogen combine with 1 atom of oxygen to give 1 molecule of water .how many grams of hydrogen are needed to react compltelywith 6.4 gram of oxygen gas? Share with your friends Share 0 veena Vasandani answered this Kindly refer to the following link:https://www.meritnation.com/ask-answer/question/two-atoms-of-hydrogen-combine-with-one-atom-of-oxygen-to-giv/atoms-and-molecules/8772145 -1 View Full Answer