Explore Westonci.ca, the top Q&A platform where your questions are answered by professionals and enthusiasts alike. Connect with a community of professionals ready to provide precise solutions to your questions quickly and accurately. Connect with a community of professionals ready to help you find accurate solutions to your questions quickly and efficiently.

Use the periodic table to calculate the molar mass of each of the following compounds. Each answer must have 2 decimal places.

Ammonia [tex]$\left( \text{NH}_3 \right)$[/tex]: [tex]$\square$[/tex] g/mol

Magnesium hydroxide [tex]$\left( \text{Mg(OH)}_2 \right)$[/tex]: [tex]$\square$[/tex] g/mol

Iron(III) oxide [tex]$\left( \text{Fe}_2\text{O}_3 \right)$[/tex]: [tex]$\square$[/tex] g/mol

Sagot :

Sure! Let's calculate the molar masses of the given compounds step by step using the atomic masses from the periodic table.

### 1. Ammonia (NH₃)

To calculate the molar mass of ammonia (NH₃), we need to sum the atomic masses of 1 nitrogen (N) atom and 3 hydrogen (H) atoms.
- Atomic mass of nitrogen (N): 14.01 g/mol
- Atomic mass of hydrogen (H): 1.01 g/mol

The molar mass of NH₃ is:
[tex]\[ \text{Molar mass of NH}_3 = 1 \times (\text{atomic mass of N}) + 3 \times (\text{atomic mass of H}) \][/tex]
[tex]\[ \text{Molar mass of NH}_3 = 1 \times 14.01 + 3 \times 1.01 \][/tex]
[tex]\[ \text{Molar mass of NH}_3 = 14.01 + 3.03 \][/tex]
[tex]\[ \text{Molar mass of NH}_3 = 17.04 \][/tex]

Thus, the molar mass of ammonia (NH₃) is 17.04 g/mol.

### 2. Magnesium hydroxide (Mg(OH)₂)

To calculate the molar mass of magnesium hydroxide (Mg(OH)₂), we need to sum the atomic masses of 1 magnesium (Mg) atom, 2 oxygen (O) atoms, and 2 hydrogen (H) atoms.
- Atomic mass of magnesium (Mg): 24.31 g/mol
- Atomic mass of oxygen (O): 16.00 g/mol
- Atomic mass of hydrogen (H): 1.01 g/mol

The molar mass of Mg(OH)₂ is:
[tex]\[ \text{Molar mass of Mg(OH)}_2 = 1 \times (\text{atomic mass of Mg}) + 2 \times (\text{atomic mass of O} + \text{atomic mass of H}) \][/tex]
[tex]\[ \text{Molar mass of Mg(OH)}_2 = 1 \times 24.31 + 2 \times (16.00 + 1.01) \][/tex]
[tex]\[ \text{Molar mass of Mg(OH)}_2 = 24.31 + 2 \times 17.01 \][/tex]
[tex]\[ \text{Molar mass of Mg(OH)}_2 = 24.31 + 34.02 \][/tex]
[tex]\[ \text{Molar mass of Mg(OH)}_2 = 58.33 \][/tex]

Thus, the molar mass of magnesium hydroxide (Mg(OH)₂) is 58.33 g/mol.

### 3. Iron(III) oxide (Fe₂O₃)

To calculate the molar mass of iron(III) oxide (Fe₂O₃), we need to sum the atomic masses of 2 iron (Fe) atoms and 3 oxygen (O) atoms.
- Atomic mass of iron (Fe): 55.85 g/mol
- Atomic mass of oxygen (O): 16.00 g/mol

The molar mass of Fe₂O₃ is:
[tex]\[ \text{Molar mass of Fe}_2\text{O}_3 = 2 \times (\text{atomic mass of Fe}) + 3 \times (\text{atomic mass of O}) \][/tex]
[tex]\[ \text{Molar mass of Fe}_2\text{O}_3 = 2 \times 55.85 + 3 \times 16.00 \][/tex]
[tex]\[ \text{Molar mass of Fe}_2\text{O}_3 = 111.70 + 48.00 \][/tex]
[tex]\[ \text{Molar mass of Fe}_2\text{O}_3 = 159.70 \][/tex]

Thus, the molar mass of iron(III) oxide (Fe₂O₃) is 159.70 g/mol.

### Summary

- Ammonia (NH₃): 17.04 g/mol
- Magnesium hydroxide (Mg(OH)₂): 58.33 g/mol
- Iron(III) oxide (Fe₂O₃): 159.70 g/mol