Nitrogen and hydrogen make ammonia. If you begin with 36.2g of nitrogen and excess hydrogen, how many grams of ammonia can you make?

Mass =  44.2 g  

Explanation:

Given data:

Mass of nitrogen reacted = 36.2 g

Mass of ammonia formed =?

Solution:

Chemical equation:

N₂ + 3H₂    →    2NH₃

Number of moles of nitrogen:

Number of moles = mass/molar mass

Number of moles = 36.2 g / 28 g/mol

Number of moles = 1.3 mol

Now we will compare the moles of nitrogen and ammonia from balanced chemical equation to determine how many moles of ammonia re formed.

                        N₂         :         NH₃

                        1            :          2

                       1.3          :         2/1×1.3 = 2.6 mol

Mass of ammonia:

Mass = number of moles × molar mass

Mass = 2.6 mol × 17 g/mol

Mass =  44.2 g  

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.