Calculating Molar Mass of Calcium Hydroxide

Oct 13, 2025 by magicalceylontours.com 121 views

Understanding the Problem

In this problem, we are tasked with determining the number of moles of calcium hydroxide ($$Ca(OH)_2$$) present in a given mass of 370.47 grams. To solve this problem, we will use the concept of molar mass and the formula for calculating moles from mass.

What is Molar Mass?

Molar mass is the mass of one mole of a substance, expressed in units of grams per mole (g/mol). It is a fundamental concept in chemistry that allows us to convert between mass and moles of a substance.

Calculating Molar Mass of Calcium Hydroxide

To calculate the molar mass of calcium hydroxide, we need to sum the atomic masses of its constituent elements: calcium (Ca), oxygen (O), and hydrogen (H). The atomic masses of these elements are:

Calcium (Ca): 40.08 g/mol
Oxygen (O): 16.00 g/mol
Hydrogen (H): 1.01 g/mol

The formula for calcium hydroxide is $$Ca(OH)_2$$, which means it consists of one calcium atom, two oxygen atoms, and two hydrogen atoms. Therefore, the molar mass of calcium hydroxide can be calculated as follows:

Molar mass of $$Ca(OH)_2$$ = (1 x 40.08 g/mol) + (2 x 16.00 g/mol) + (2 x 1.01 g/mol) = 40.08 g/mol + 32.00 g/mol + 2.02 g/mol = 74.10 g/mol

Calculating Moles of Calcium Hydroxide

Now that we have the molar mass of calcium hydroxide, we can use the formula to calculate the number of moles present in a given mass:

moles = mass / molar mass

In this case, the mass of calcium hydroxide is 370.47 grams, and the molar mass is 74.10 g/mol. Plugging these values into the formula, we get:

moles = 370.47 g / 74.10 g/mol = 5.00 mol

Conclusion

Therefore, the number of moles of calcium hydroxide present in 370.47 grams of $$Ca(OH)_2$$ is 5.00 mol.

Answer

The correct answer is C. 5.

Additional Information

Calcium hydroxide is a strong base that is commonly used in various applications, including water treatment, construction, and pharmaceuticals. It is also known as slaked lime or calcium oxide.

References

CRC Handbook of Chemistry and Physics, 97th Edition
IUPAC Compendium of Chemical Terminology, 2nd Edition

Q: What is calcium hydroxide?

A: Calcium hydroxide, also known as slaked lime or calcium oxide, is a chemical compound with the formula $$Ca(OH)_2$$. It is a strong base that is commonly used in various applications, including water treatment, construction, and pharmaceuticals.

Q: What are the properties of calcium hydroxide?

A: Calcium hydroxide is a white, odorless, and crystalline solid that is highly soluble in water. It has a high pH value, making it a strong base. It is also highly reactive and can react with acids to form salts and water.

Q: What are the uses of calcium hydroxide?

A: Calcium hydroxide has a wide range of applications, including:

Water treatment: Calcium hydroxide is used to remove impurities and contaminants from water.
Construction: Calcium hydroxide is used as a building material, particularly in the production of cement and concrete.
Pharmaceuticals: Calcium hydroxide is used as an excipient in some pharmaceutical products.
Paper production: Calcium hydroxide is used to improve the strength and durability of paper.

Q: Is calcium hydroxide safe to handle?

A: Calcium hydroxide can be hazardous if not handled properly. It can cause skin and eye irritation, and inhalation of its dust can lead to respiratory problems. It is essential to wear protective gear, including gloves, goggles, and a mask, when handling calcium hydroxide.

Q: How is calcium hydroxide produced?

A: Calcium hydroxide is produced by the reaction of calcium oxide (lime) with water. The reaction is as follows:

CaO + H_2O \rightarrow Ca(OH)_2

Calcium oxide is obtained from limestone (calcium carbonate) through a process known as calcination.

Q: What are the common mistakes to avoid when handling calcium hydroxide?

A: Some common mistakes to avoid when handling calcium hydroxide include:

Not wearing protective gear, including gloves, goggles, and a mask.
Not handling calcium hydroxide in a well-ventilated area.
Not storing calcium hydroxide in a cool, dry place.
Not following the recommended dosage when using calcium hydroxide in water treatment or other applications.

Q: Can calcium hydroxide be used as a substitute for other chemicals?

A: Calcium hydroxide can be used as a substitute for other chemicals in some applications, but it is essential to consider the specific requirements of the application and the properties of calcium hydroxide before making a substitution.

Q: What are the environmental concerns associated with calcium hydroxide?

A: Calcium hydroxide can have environmental concerns, including:

Release of calcium ions into waterways, which can lead to eutrophication and harm aquatic life.
Release of carbon dioxide during its production and use.
Generation of waste products, including calcium carbonate and other byproducts.

Q: Can calcium hydroxide be recycled or reused?

A: Yes, calcium hydroxide can be recycled or reused in some applications, including water treatment and construction. However, the feasibility of recycling or reusing calcium hydroxide depends on the specific application and the properties of the calcium hydroxide.

Q: What are the future prospects for calcium hydroxide?

A: The future prospects for calcium hydroxide are promising, with increasing demand for its use in water treatment, construction, and other applications. However, the industry must address environmental concerns and develop more sustainable production and use practices to meet growing demand.