For the reaction ch4 + 2o2 = co2 + 2h2o, how many moles of water are produced from the combustion of 12.5 moles of methane?

25 moles of water are produced.

Explanation:

Combustion is a type of chemical reaction in which fuel is reacted with oxygen to form carbon dioxide and water.

Example:  

According to stoichiometry:

1 mole of methane on combustion produces= 2 moles of water

12.5 moles of methane on combustion produces= moles of water

Thus 25 moles of water are produced from the combustion of 12.5 moles of methane.

astronomers such as edwin hubble.