What is the molar mass of citric acid (H3C6H5O7)?
The Correct Answer and Explanation is:
To determine the molar mass of citric acid (chemical formula ( \text{C}_6\text{H}_8\text{O}_7 )), we need to sum the molar masses of all the individual atoms present in the molecule. Citric acid contains carbon (C), hydrogen (H), and oxygen (O) atoms.
- Counting Atoms:
- Carbon (C): 6 atoms
- Hydrogen (H): 8 atoms
- Oxygen (O): 7 atoms
- Molar Mass of Each Element:
- The molar mass of carbon (C) is approximately ( 12.01 \, \text{g/mol} ).
- The molar mass of hydrogen (H) is approximately ( 1.01 \, \text{g/mol} ).
- The molar mass of oxygen (O) is approximately ( 16.00 \, \text{g/mol} ).
- Calculating Total Molar Mass:
- For carbon:
[
6 \, \text{C} \times 12.01 \, \text{g/mol} = 72.06 \, \text{g/mol}
] - For hydrogen:
[
8 \, \text{H} \times 1.01 \, \text{g/mol} = 8.08 \, \text{g/mol}
] - For oxygen:
[
7 \, \text{O} \times 16.00 \, \text{g/mol} = 112.00 \, \text{g/mol}
]
- Adding the Contributions:
Now we add the contributions of each element together to find the total molar mass of citric acid:
[
72.06 \, \text{g/mol} + 8.08 \, \text{g/mol} + 112.00 \, \text{g/mol} = 192.14 \, \text{g/mol}
]
Thus, the molar mass of citric acid is approximately 192.14 g/mol.
Importance of Molar Mass
The molar mass is crucial in chemistry as it allows for the conversion between grams of a substance and moles, facilitating stoichiometric calculations in reactions. Knowing the molar mass is essential for preparing solutions, conducting titrations, and understanding the quantitative aspects of chemical reactions. Citric acid, being a common organic acid found in citrus fruits, is widely used in food and beverages, as well as in various biochemical processes. Its molar mass plays a key role in calculations involving its concentration in solutions, making it fundamental in both analytical and preparative chemistry.