The molar mass of a chemical compound is a fundamental concept in chemistry, representing the mass of one mole of that compound. In the case of potassium bromide (KBr), a salt formed by the reaction of potassium and bromine, understanding its molar mass is crucial for various chemical calculations and applications.
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Potassium bromide, with the chemical formula KBr, consists of one potassium (K) atom and one bromine (Br) atom. The atomic mass of potassium is approximately 39.0983 grams per mole (g/mol), and the atomic mass of bromine is about 79.904 g/mol. To find the molar mass of KBr, we simply add the atomic masses of potassium and bromine together.
Calculation of Molar Mass
The calculation for the molar mass of KBr is as follows: Molar mass of KBr = Atomic mass of K + Atomic mass of Br = 39.0983 g/mol + 79.904 g/mol. Performing this calculation yields a molar mass of approximately 119.0023 g/mol for potassium bromide.
| Element | Atomic Mass (g/mol) |
|---|---|
| Potassium (K) | 39.0983 |
| Bromine (Br) | 79.904 |
| KBr (Potassium Bromide) | 119.0023 |
Key Points
- The atomic mass of potassium is approximately 39.0983 g/mol.
- The atomic mass of bromine is about 79.904 g/mol.
- The molar mass of KBr is calculated by adding the atomic masses of potassium and bromine, resulting in approximately 119.0023 g/mol.
- Understanding the molar mass of compounds is vital for chemical calculations, including determining the number of moles in a given mass and preparing solutions of specific concentrations.
- The molar mass of a compound is a fundamental property that reflects the mass of one mole of that substance.
Applications and Considerations
Potassium bromide has various applications, including its use in photography, as a sedative, and in the manufacture of pharmaceuticals. Knowing the molar mass of KBr can help in the precise preparation of these applications, ensuring the correct proportions of reactants are used.
Practical Applications
In photography, potassium bromide is used as a restrainer in the development process, helping to control the amount of silver bromide that is reduced to silver, thus affecting the contrast of the image. The molar mass of KBr is crucial in calculating the amount of potassium bromide needed for a specific volume of developer solution.
Furthermore, the molar mass of compounds like potassium bromide is essential in educational settings, where understanding and calculating molar masses are fundamental skills taught in chemistry classes. It helps students grasp the concept of moles, Avogadro's number, and stoichiometry, which are central to chemical calculations and reactions.
What is the significance of knowing the molar mass of a compound like potassium bromide?
+Knowing the molar mass of potassium bromide is significant because it allows for the precise calculation of the amount of substance needed for various applications, including chemical reactions, solution preparations, and industrial processes.
How is the molar mass of KBr calculated?
+The molar mass of KBr is calculated by adding the atomic masses of potassium (K) and bromine (Br), which are approximately 39.0983 g/mol and 79.904 g/mol, respectively.
What are some common applications of potassium bromide?
+Potassium bromide has applications in photography, as a sedative, and in the manufacture of pharmaceuticals. It is also used in various chemical reactions and as a source of bromide ions.
In conclusion, the molar mass of potassium bromide, calculated as approximately 119.0023 g/mol, is a critical piece of information for various chemical and industrial applications. Its accurate calculation and understanding are fundamental to chemistry, reflecting the mass of one mole of the substance and facilitating precise chemical calculations and reactions.
