Hydrogen fuel cells are a promising alternative to gasoline engines in part because they release water instead of carbon dioxide. In a hydrogen fuel cell, hydrogen gas (H2) and oxygen gas (02) react to make water as shown below. Which of the following statements is a true statement about how this reaction occurs? 2H2(g) + O2(g) → 2 H2O(g) A. A molecule of H2 and a molecule of o2 collide B. Two molecules of H2 and a molecule of O2 must collide at one time C. An O-H bond must break. D. An H-H bond must form E. The reactants must undergo a change of state for this reaction to occur

The correct answer is option (B) Two molecules of H2 and a molecule of O2 must collide at one time

Explanation:

2H2(g) + O2(g) → 2 H2O(g)

   2             1            2

Considering the given reaction, for water molecule to be form, two molecules of hydrogen and one molecule of oxygen must collide at the same time. The product obtained from the collision is two molecules of water as steam. 2 H2O(g)

From the equation

2H2(g) + O2(g) → 2 H2O(g

it is obvious as hydrogen fuels are promising alternative Two molecules of H2 and a molecule of O2 must collide at one time is the best option.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.