What is the percentage composition by mass of nitrogen in ammonia?

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Answer 1 · 2017-08-30T06:58:47

Well it is simply $"Mass of nitrogen"/"Mass of nitrogen and hydrogen"xx100%$

And thus taking molar masses......we get:

$(14.01*g*mol^-1)/(14.01*g*mol^-1+3xx1.00794*g*mol^-1)xx100%$

$~=80%$

Answer 2 · 2017-08-30T07:02:46

The mass percent of $"N"$ in $"NH"_3$ is $82.244%$ .

Divide the mass of $"N"$ by the mass of $"NH"_3$ , then multiply by $100$

The chemical formula for ammonia is $"NH"_3$ . The formula indicates that in each mole of $"NH"_3$ , there is one mole of $"N"$ atoms.

The molar mass of ammonia is $"17.031 g/mol"$ . The molar mass of $"N"$ is $"14.007 g/mol"$ .

$"mass percent N"$ $=$ $(14.007color(red)cancel(color(black)("g/mol")))/(17.031color(red)cancel(color(black)("g/mol")))xx100="82.244%"$