If the reaction begins with 12.0 grams of O2 how many grams of NO2 will be produced given the following equation: 2 NO + O2 --> 2 NO2

69g

Explanation:

Given reaction expression:

             2NO  +  O₂ →2 NO₂

Unknown:

Mass of NO₂ produced  = ?

Solution:

To solve this problem, let us use the mole concept. We solve from the known to the unknown

In this regard, find the number of moles of O₂ given;

  Number of moles  =  

Molar mass of O₂  = 2(16g/mol)  = 32g/mol

  Number of moles  =   = 0.75mole

From the balanced reaction equation;

    1 mole of O₂ will produce 2mole of NO₂;

   0.75 mole of O₂ will produce 1.5mole of NO₂

Therefore, mass of NO₂;

  Mass of NO₂ = number of moles x molar mass

  Molar mass of NO₂ = 14 + 2(16) = 46g/mol

  Molar mass of NO₂ = 1.5 x 46  = 69g

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the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.