Question

. Calculate the mass percent composition of nitrogen in each compound. (a) N2O (b) NO (c) NO2 (d) N2O5

Short answer

The mass percent compositions of nitrogen are: (a) 63.65% for N2O, (b) 46.68% for NO, (c) 30.43% for NO2, and (d) 25.93% for N2O5.

Step-by-step solution

Calculate the molar mass of N2O

To find the molar mass of N2O, multiply the atomic mass of nitrogen (N) by 2 and add the atomic mass of oxygen (O). The atomic mass of N is approximately 14.01 g/mol and O is approximately 16.00 g/mol. Molar mass of N2O = (2 * 14.01 g/mol) + (1 * 16.00 g/mol).

Calculate the mass percent of nitrogen in N2O

Divide the total mass of nitrogen in the compound by the molar mass of N2O and multiply by 100% to get the mass percent composition of nitrogen.Percent of N in N2O = [(2 * 14.01 g/mol) / Molar mass of N2O] * 100%.

Repeat process for NO

Repeat the same process for NO. Molar mass of NO = (1 * 14.01 g/mol) + (1 * 16.00 g/mol), and find the percent composition of N accordingly.

Repeat process for NO2

Calculate the molar mass of NO2, then determine the mass percent of nitrogen. Molar mass of NO2 = (1 * 14.01 g/mol) + (2 * 16.00 g/mol).

Repeat process for N2O5

Find the molar mass of N2O5 and calculate the mass percent of nitrogen. Molar mass of N2O5 = (2 * 14.01 g/mol) + (5 * 16.00 g/mol).

Final calculation and comparison

Calculate the mass percent for each compound using the respective molar masses found in the previous steps and compare the mass percent composition of nitrogen in each compound.

Key concepts

Molar Mass Calculation

Understanding the molar mass of a compound is foundational in chemistry. It's the first step in many exercises, including calculating the mass percent composition of an element in a compound. To calculate the molar mass, we sum the masses of all the atoms within a molecule.

For example, in the compound N2O, which is composed of 2 nitrogen atoms and 1 oxygen atom, the molar mass is found by adding together the mass of two nitrogen atoms and one oxygen atom. The atomic mass of nitrogen (N) is approximately 14.01 grams per mole (g/mol) and of oxygen (O) is approximately 16.00 g/mol. Therefore, the calculation is as follows: \[ \text{Molar mass of N2O} = (2 \times 14.01 \, \text{g/mol}) + (1 \times 16.00 \, \text{g/mol}) \].

This simple arithmetic step lays the groundwork for understanding the composition of the compound and is an essential skill in any chemical calculation.

Chemical Compound Composition

Learning about the chemical compound composition is crucial for students to grasp how elements come together to form substances with different properties. Each element contributes to the overall characteristics of a compound, and understanding the mass percent composition helps to illuminate this.

The mass percent composition of an element within a compound is the fraction of the total mass of the compound that is due to that element. It shows the relative amount of each element present. To calculate this, identify the mass of the individual element in the compound and divide it by the molar mass of the whole compound, multiplying the result by 100% to get a percentage.

For instance, in the compound NO2, nitrogen's mass contribution is calculated as \[ \text{Percent of N in NO2} = \left( \frac{1 \times 14.01 \, \text{g/mol}}{\text{Molar mass of NO2}} \right) \times 100% \].

Realizing the composition enables students to predict and explain properties such as reactivity, boiling and melting points, and even the biological activity of compounds.

Stoichiometry

Stoichiometry is the concept central to chemical reactions and involves the quantitative relationships between reactants and products. It relies heavily on the principles of the conservation of mass and the consistent ratios defined by chemical formulas.

When working on exercises like calculating mass percent composition, you're engaging with stoichiometry to relate the mass of an element to the mass of the entire compound. Each step—from calculating molar mass to using it for determining mass percent—requires a stoichiometric perspective to understand the proportions and mass relationships of the elements involved.

Exploring Ratios

In stoichiometry, we detail the ratio of elements in compounds and reactants to products in a reaction. Using the molar mass as a conversion factor, one can relate these ratios to real-world quantities, which is vital when scaling reactions for industrial use or predicting yield in a laboratory experiment.