Chemistry, 15.10.2019 02:30 lexhorton2002

What is the percent composition by mass of nitrogen in (nh4)2co3 (gram-formula mass = 96.0 g/mol)?

(1) 14.6%
(2) 29.2%
(3) 58.4%
(4) 87.5%

Answers: 1

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Answers

The percentage composition by mass of nitrogen in ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ is $\boxed{\left( 2 \right){\text{ 29}}{\text{.2 \% }}}$ .

Further explanation:

The most commonly applied concentration terms are as follows:

1. Molality

2. Mole fraction

3. Molarity

4. Parts per million

5. Mass percent

6. Volume percent

7. Percentage composition

The given compound is ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ . It contains two atoms of nitrogen, eight atoms of hydrogen, one atom of carbon and three atoms of oxygen.

The mass of nitrogen in ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ can be calculated as follows:

${\text{Mass of N}} =\left( {{\text{Number of nitrogen atoms}}} \right)\left( {{\text{Molar mass of nitrogen}}} \right)$ …… (1)

The number of N atoms in ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ is 2.

The molar mass of nitrogen is 14.01 g/mol.

Substitute these values in equation (1).

$\begin{aligned}{\text{Mass of nitrogen}} &= \left( {\text{2}} \right)\left( {{\text{14}}{\text{.01 g/mol}}} \right)\\&= 28.02{\text{ g/mol}}\\\end{aligned}$

The formula to calculate the percentage composition of N in ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ is as follows:

${\text{\% composition of N}} = \left( {\dfrac{{{\text{Mass of N}}}}{{{\text{Mass of }}{{\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)}_{\text{2}}}{\text{C}{{\text{O}}_{\text{3}}}}}} \right){\text{100 \% }}$ …… (2)

The mass of N is 28.02 g/mol.

The mass of ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ is 96.0 g/mol.

Substitute these values in equation (2).

$\begin{aligned}{\text{\% composition of N}} &= \left( {\frac{{{\text{28}}{\text{.02 g/mol}}}}{{{\text{96}}{\text{.0 g/mol}}}}} \right){\text{100 \% }}\\&= {\text{29}}{\text{.1875 \% }} \\ &\approx {\text{2}}{\text{.92 \%}}\\\end{aligned}$

Therefore the percentage composition by mass of nitrogen in ${\left( {{\text{N}}{{\text{H}}_{\text{4}}}} \right)_{\text{2}}}{\text{C}}{{\text{O}}_{\text{3}}}$ is 29.2 %.

Learn more:

Calculate the moles of chlorine in 8 moles of carbon tetrachloride: link What is the concentration of alcohol in terms of molarity? link

Answer details:

Grade: Senior School

Chapter: Concentration terms

Subject: Chemistry

Keywords: (NH4)2CO3, N, nitrogen, mass, 2.92 %, 96.0 g/mol, 28.02 g/mol, nitrogen, hydrogen, carbon, oxygen, mass of N, mass of (NH4)2CO3.

Answer from: staxeeyy767

The % composition of nitrogen is 29.166% ~ 29.2%. Thus option 2 is correct.

The percent composition of nitrogen in ammonium carbonate can be calculated as:

% Composition = $\rm \dfrac{mass\;of\;element}{mass\;of\lcompound}\;\times\;100$