Chemistry problem

Question

In the explosion of a hydrogen-filled balloon, 0.46 g of hydrogen reacted with 4.1 g of oxygen to form how many grams of water vapor? (Water vapor is the only product.)

Answer 1

Hydrogen H₂ reacts with oxygen O₂ to produce water H₂O according to the following proportion:

 

2 moles of H₂ react with 1 mole of O₂ to produce 2 moles of H₂O (balanced equation)

 

0.46 g of H₂ is 0.228 moles of H₂ which are going to react with 0.114 moles of O₂ (half the moles of H₂ according to the above proportion) to produce 0.228 moles of H₂O (again, according to above proportion). You can check there is more than enough O₂ to consume all of the H₂ and there will be some O₂ leftover.

 

0.228 moles of water in grams is 0.228 mol * (18.02 g/mol) = you do the math (the result in grams)

 

Note: if you don't understand the concept of molar mass and proportions it will be hard for you to solve chemical reactions.