Calculate Moles And Atoms In 6.12 G Of Sodium (Na)

Aug 4, 2025 by Brainly ES FTUNILA 51 views

Let's dive into the fascinating world of chemistry and explore how to calculate the number of moles and atoms in a given mass of a substance. In this article, we'll specifically focus on sodium (Na) and work through a step-by-step calculation to determine the number of moles and atoms present in 6.12 g of sodium. So, buckle up and get ready to learn some cool chemistry concepts!

Understanding the Basics

Before we jump into the calculations, it's crucial to grasp a few fundamental concepts. These concepts will serve as the building blocks for our understanding and enable us to solve the problem effectively.

Moles: The Chemist's Counting Unit

In chemistry, we often deal with incredibly large numbers of atoms and molecules. To simplify things, chemists use a unit called the mole (mol). One mole is defined as the amount of substance that contains as many entities (atoms, molecules, ions, etc.) as there are atoms in 12 grams of carbon-12. This number, known as Avogadro's number, is approximately 6.022 x 10^23 entities per mole.

Think of a mole like a dozen, but on a much grander scale. Just as a dozen represents 12 items, a mole represents 6.022 x 10^23 entities. It's a convenient way to count vast quantities of atoms and molecules in chemical reactions.

Molar Mass: Connecting Mass and Moles

The molar mass of a substance is the mass of one mole of that substance, expressed in grams per mole (g/mol). It's a crucial link between the mass of a substance and the number of moles it contains. The molar mass of an element is numerically equal to its atomic mass, which can be found on the periodic table.

For example, the atomic mass of sodium (Na) is approximately 22.99 atomic mass units (amu). Therefore, the molar mass of sodium is 22.99 g/mol. This means that one mole of sodium weighs 22.99 grams.

Avogadro's Number: The Key to Counting Atoms

As mentioned earlier, Avogadro's number (6.022 x 10^23) is the number of entities (atoms, molecules, ions, etc.) in one mole of a substance. This number is a cornerstone of chemistry, allowing us to convert between moles and the actual number of particles.

Imagine you have a mole of sodium atoms. Avogadro's number tells us that you have 6.022 x 10^23 individual sodium atoms. This conversion factor is essential for calculating the number of atoms in a given sample.

Problem Breakdown: Calculating Moles and Atoms of Sodium

Now that we have a solid grasp of the fundamental concepts, let's tackle the problem at hand. We are given 6.12 g of sodium (Na) and asked to determine:

a. The number of moles represented by this mass. b. The number of sodium atoms present in this mass.

To solve this problem, we'll use the concepts of molar mass and Avogadro's number. Here's a step-by-step approach:

a. Calculating Moles

Identify the given information:
- Mass of sodium (Na) = 6.12 g
Find the molar mass of sodium (Na):
- From the periodic table, the molar mass of Na is approximately 22.99 g/mol.
Use the molar mass to convert grams to moles:
- We know that 1 mole of Na weighs 22.99 g.
- We can set up a conversion factor:
```
Moles of Na = (Mass of Na) / (Molar mass of Na)
```
- Plug in the values:
```
Moles of Na = (6.12 g) / (22.99 g/mol)
```
Calculate the result:
```
Moles of Na ≈ 0.266 mol
```
Therefore, 6.12 g of sodium represents approximately 0.266 moles.

b. Calculating Atoms

Recall Avogadro's number:
- 1 mole of any substance contains 6.022 x 10^23 entities (atoms, molecules, etc.).
Use Avogadro's number to convert moles to atoms:
- We know that 1 mole of Na contains 6.022 x 10^23 Na atoms.
- We can set up a conversion factor:
```
Atoms of Na = (Moles of Na) x (Avogadro's number)
```
Plug in the values:
- We calculated that we have approximately 0.266 moles of Na.
- Avogadro's number is 6.022 x 10^23 atoms/mol.
```
Atoms of Na = (0.266 mol) x (6.022 x 10^23 atoms/mol)
```
Calculate the result:
```
Atoms of Na ≈ 1.60 x 10^23 atoms
```
Therefore, 6.12 g of sodium contains approximately 1.60 x 10^23 sodium atoms.

Putting It All Together: The Solution

Let's summarize our findings:

a. Moles of sodium (Na) in 6.12 g: Approximately 0.266 moles b. Number of sodium (Na) atoms in 6.12 g: Approximately 1.60 x 10^23 atoms

We successfully calculated the number of moles and atoms in 6.12 g of sodium by utilizing the concepts of molar mass and Avogadro's number. These calculations are fundamental in chemistry and allow us to quantify the amounts of substances involved in chemical reactions.

Key Takeaways

Moles are the chemist's counting unit, representing 6.022 x 10^23 entities.
Molar mass connects the mass of a substance to the number of moles.
Avogadro's number (6.022 x 10^23) is the number of entities in one mole.
We can use molar mass to convert grams to moles and Avogadro's number to convert moles to atoms.

Practice Problems

To solidify your understanding, try solving these practice problems:

Calculate the number of moles in 10.0 g of carbon (C).
Determine the number of molecules in 2.5 moles of water (H2O).
How many grams are there in 0.75 moles of iron (Fe)?

By working through these problems, you'll gain confidence in your ability to apply these concepts in various chemical calculations.

Conclusion

Calculating moles and atoms is a fundamental skill in chemistry. By understanding the concepts of molar mass and Avogadro's number, we can effectively quantify the amounts of substances and perform various chemical calculations. So, keep practicing, and you'll become a chemistry whiz in no time!