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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]$\square \, \text{g/mol}$[/tex]

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

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



Answer :

GinnyAnswer
Absolutely, let's calculate the molar mass of each compound step-by-step using the periodic table.

### Ammonia (NH₃)

1. Identify the molar mass of each element:
- Nitrogen (N): 14.01 g/mol
- Hydrogen (H): 1.01 g/mol

2. Count the atoms in the compound:
- 1 Nitrogen atom
- 3 Hydrogen atoms

3. Calculate the total molar mass:
[tex]\[ \text{Molar mass of } NH_3 = (1 \times 14.01) + (3 \times 1.01) \][/tex]

4. Simplify the calculation:
[tex]\[ \text{Molar mass of } NH_3 = 14.01 + 3.03 = 17.04 \, \text{g/mol} \][/tex]

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

### Magnesium Hydroxide (Mg(OH)â‚‚)

1. Identify the molar mass of each element:
- Magnesium (Mg): 24.31 g/mol
- Oxygen (O): 16.00 g/mol
- Hydrogen (H): 1.01 g/mol

2. Count the atoms in the compound:
- 1 Magnesium atom
- 2 Oxygen atoms
- 2 Hydrogen atoms

3. Calculate the total molar mass:
[tex]\[ \text{Molar mass of } Mg(OH)_2 = (1 \times 24.31) + (2 \times (16.00 + 1.01)) \][/tex]

4. Simplify the calculation:
[tex]\[ \text{Molar mass of } Mg(OH)_2 = 24.31 + 2 \times 17.01 = 24.31 + 34.02 = 58.33 \, \text{g/mol} \][/tex]

So, the molar mass of magnesium hydroxide (Mg(OH)â‚‚) is 58.33 g/mol.

### Iron(III) Oxide (Fe₂O₃)

1. Identify the molar mass of each element:
- Iron (Fe): 55.85 g/mol
- Oxygen (O): 16.00 g/mol

2. Count the atoms in the compound:
- 2 Iron atoms
- 3 Oxygen atoms

3. Calculate the total molar mass:
[tex]\[ \text{Molar mass of } Fe_2O_3 = (2 \times 55.85) + (3 \times 16.00) \][/tex]

4. Simplify the calculation:
[tex]\[ \text{Molar mass of } Fe_2O_3 = 111.70 + 48.00 = 159.70 \, \text{g/mol} \][/tex]

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

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