The Molar Mass of Aluminum Hydroxide

Oct 13, 2025 by wbrum.org 115 views

Understanding the Basics of Atomic Mass and Molar Mass

The atomic mass of an element is the average mass of a single atom of that element, expressed in units of atomic mass units (amu) or grams per mole (g/mol). In the case of hydrogen, its atomic mass is 1.01 amu or 1.01 g/mol. However, when it comes to compounds like aluminum hydroxide (Al(OH)3), the situation becomes more complex.

The Molar Mass of Aluminum Hydroxide

To determine the mass of hydrogen in one mole of aluminum hydroxide, we need to calculate the molar mass of the compound. The molar mass of a compound is the sum of the atomic masses of its constituent elements, multiplied by their respective numbers of atoms in the formula unit.

The formula unit of aluminum hydroxide is Al(OH)3, which means it consists of one aluminum atom, three oxygen atoms, and three hydrogen atoms. The atomic masses of these elements are:

Aluminum (Al): 26.98 g/mol
Oxygen (O): 16.00 g/mol
Hydrogen (H): 1.01 g/mol

Calculating the Molar Mass of Aluminum Hydroxide

To calculate the molar mass of aluminum hydroxide, we multiply the atomic masses of its constituent elements by their respective numbers of atoms in the formula unit, and then sum the results:

Molar mass of Al(OH)3 = (1 x 26.98) + (3 x 16.00) + (3 x 1.01) Molar mass of Al(OH)3 = 26.98 + 48.00 + 3.03 Molar mass of Al(OH)3 = 78.01 g/mol

Determining the Mass of Hydrogen in One Mole of Aluminum Hydroxide

Now that we have the molar mass of aluminum hydroxide, we can determine the mass of hydrogen in one mole of the compound. Since the formula unit of aluminum hydroxide contains three hydrogen atoms, we multiply the atomic mass of hydrogen by 3:

Mass of hydrogen in one mole of Al(OH)3 = 3 x 1.01 g/mol Mass of hydrogen in one mole of Al(OH)3 = 3.03 g

Conclusion

In conclusion, the mass of hydrogen in one mole of aluminum hydroxide is 3.03 g. This is because the formula unit of aluminum hydroxide contains three hydrogen atoms, and the atomic mass of hydrogen is 1.01 g/mol.

Answer

The correct answer is C. 3.01 g.

Additional Information

The atomic mass of hydrogen is 1.01 amu or 1.01 g/mol.
The molar mass of aluminum hydroxide is 78.01 g/mol.
The mass of hydrogen in one mole of aluminum hydroxide is 3.03 g.

References

[1] CRC Handbook of Chemistry and Physics, 97th Edition.
[2] National Institute of Standards and Technology (NIST) Chemistry WebBook.

Frequently Asked Questions

Q: What is the atomic mass of hydrogen? A: The atomic mass of hydrogen is 1.01 amu or 1.01 g/mol.
Q: What is the molar mass of aluminum hydroxide? A: The molar mass of aluminum hydroxide is 78.01 g/mol.
Q: What is the mass of hydrogen in one mole of aluminum hydroxide? A: The mass of hydrogen in one mole of aluminum hydroxide is 3.03 g.
Frequently Asked Questions: The Atomic Mass of Hydrogen in Aluminum Hydroxide ================================================================================

Q: What is the atomic mass of hydrogen?

A: The atomic mass of hydrogen is 1.01 amu or 1.01 g/mol. This is the average mass of a single hydrogen atom, and it is a fundamental constant in chemistry.

Q: What is the molar mass of aluminum hydroxide?

A: The molar mass of aluminum hydroxide is 78.01 g/mol. This is the sum of the atomic masses of its constituent elements, multiplied by their respective numbers of atoms in the formula unit.

Q: What is the mass of hydrogen in one mole of aluminum hydroxide?

A: The mass of hydrogen in one mole of aluminum hydroxide is 3.03 g. This is because the formula unit of aluminum hydroxide contains three hydrogen atoms, and the atomic mass of hydrogen is 1.01 g/mol.

Q: How do I calculate the molar mass of a compound?

A: To calculate the molar mass of a compound, you need to multiply the atomic masses of its constituent elements by their respective numbers of atoms in the formula unit, and then sum the results.

Q: What is the difference between atomic mass and molar mass?

A: The atomic mass of an element is the average mass of a single atom of that element, while the molar mass of a compound is the sum of the atomic masses of its constituent elements, multiplied by their respective numbers of atoms in the formula unit.

Q: Can I use the atomic mass of hydrogen to calculate the mass of hydrogen in a compound?

A: Yes, you can use the atomic mass of hydrogen to calculate the mass of hydrogen in a compound. However, you need to multiply the atomic mass of hydrogen by the number of hydrogen atoms in the compound.

Q: What is the significance of the atomic mass of hydrogen in chemistry?

A: The atomic mass of hydrogen is a fundamental constant in chemistry, and it is used to calculate the molar mass of compounds and the mass of elements in a compound.

Q: Can I use the molar mass of aluminum hydroxide to calculate the mass of hydrogen in a different compound?

A: No, you cannot use the molar mass of aluminum hydroxide to calculate the mass of hydrogen in a different compound. The molar mass of a compound is specific to that compound, and you need to calculate the molar mass of the new compound using the atomic masses of its constituent elements.

Q: What are some common applications of the atomic mass of hydrogen in chemistry?

A: The atomic mass of hydrogen is used in a variety of applications in chemistry, including:

Calculating the molar mass of compounds
Determining the mass of elements in a compound
Understanding the properties of elements and compounds
Developing new compounds and materials

Q: Can I find the atomic mass of hydrogen in a chemistry textbook or online resource?

A: Yes, you can find the atomic mass of hydrogen in a chemistry textbook or online resource. The atomic mass of hydrogen is a well-established constant in chemistry, and it is widely available in chemistry textbooks and online resources.

Q: What are some common mistakes to avoid when working with the atomic mass of hydrogen?

A: Some common mistakes to avoid when working with the atomic mass of hydrogen include:

Confusing the atomic mass of hydrogen with the molar mass of a compound
Failing to multiply the atomic mass of hydrogen by the number of hydrogen atoms in a compound
Using an incorrect value for the atomic mass of hydrogen
Failing to consider the significance of the atomic mass of hydrogen in chemistry.