Expressing the Answer Using Four Significant Figures

Oct 13, 2025 by wbrum.org 58 views

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Introduction

In chemistry, the concept of a mole is crucial for understanding the relationships between the amount of substance and the number of particles present. A mole of any substance contains a specific number of particles, known as Avogadro's number, which is approximately 6.022 x 10^23 particles. In this article, we will explore how many carbon atoms are present in a mole of $^{12}\text{C}$ , a specific isotope of carbon.

What is a Mole?

A mole is a unit of measurement that represents 6.022 x 10^23 particles of a substance. This number is known as Avogadro's number and is a fundamental constant in chemistry. The mole is used to express the amount of substance in a sample, and it is a key concept in understanding chemical reactions and stoichiometry.

What is $^{12}\text{C}$ ?

$^{12}\text{C}$ is a specific isotope of carbon that has 6 protons and 6 neutrons in its atomic nucleus. The superscript "12" represents the mass number of the isotope, which is the sum of the number of protons and neutrons in the nucleus. The subscript "C" represents the element carbon.

Calculating the Number of Carbon Atoms in a Mole of $^{12}\text{C}$

To calculate the number of carbon atoms in a mole of $^{12}\text{C}$ , we can use Avogadro's number. Since a mole of any substance contains 6.022 x 10^23 particles, a mole of $^{12}\text{C}$ will also contain 6.022 x 10^23 carbon atoms.

Expressing the Answer Using Four Significant Figures

To express the answer using four significant figures, we can round the number of carbon atoms to 6.022 x 10^23.

Conclusion

In conclusion, a mole of $^{12}\text{C}$ contains 6.022 x 10^23 carbon atoms. This number is a fundamental constant in chemistry and is used to express the amount of substance in a sample. Understanding the concept of a mole and Avogadro's number is crucial for understanding chemical reactions and stoichiometry.

Frequently Asked Questions

Q: What is a mole?

A: A mole is a unit of measurement that represents 6.022 x 10^23 particles of a substance.

Q: What is $^{12}\text{C}$ ?

A: $^{12}\text{C}$ is a specific isotope of carbon that has 6 protons and 6 neutrons in its atomic nucleus.

Q: How many carbon atoms are present in a mole of $^{12}\text{C}$ ?

A: A mole of $^{12}\text{C}$ contains 6.022 x 10^23 carbon atoms.

References

IUPAC. (2019). Compendium of Chemical Terminology, 2nd ed. (the "Gold Book").
National Institute of Standards and Technology. (2020). Avogadro's Number.

Introduction

In our previous article, we explored the concept of a mole and Avogadro's number, and how they are used to express the amount of substance in a sample. In this article, we will answer some frequently asked questions about the mole and Avogadro's number, and provide further clarification on these important concepts in chemistry.

Q&A

Q: What is the difference between a mole and a gram?

A: A mole is a unit of measurement that represents 6.022 x 10^23 particles of a substance, while a gram is a unit of mass. One mole of any substance has a mass equal to its molecular weight in grams.

Q: How do I calculate the number of moles in a sample?

A: To calculate the number of moles in a sample, you need to know the mass of the sample and the molecular weight of the substance. You can use the formula: number of moles = mass of sample / molecular weight.

Q: What is the significance of Avogadro's number?

A: Avogadro's number is a fundamental constant in chemistry that represents the number of particles in one mole of a substance. It is used to express the amount of substance in a sample and is a key concept in understanding chemical reactions and stoichiometry.

Q: Can I use Avogadro's number to calculate the number of particles in a sample?

A: Yes, you can use Avogadro's number to calculate the number of particles in a sample. Simply multiply the number of moles in the sample by Avogadro's number.

Q: What is the difference between a mole of atoms and a mole of molecules?

A: A mole of atoms represents 6.022 x 10^23 atoms of a substance, while a mole of molecules represents 6.022 x 10^23 molecules of a substance. The key difference is that atoms are individual particles, while molecules are groups of atoms bonded together.

Q: Can I use the mole concept to calculate the number of particles in a sample of a mixture?

A: Yes, you can use the mole concept to calculate the number of particles in a sample of a mixture. However, you need to know the composition of the mixture and the molecular weight of each component.

Common Misconceptions

Misconception 1: A mole is a unit of mass.

Reality: A mole is a unit of measurement that represents 6.022 x 10^23 particles of a substance.

Misconception 2: Avogadro's number is a variable.

Reality: Avogadro's number is a fundamental constant in chemistry that represents the number of particles in one mole of a substance.

Misconception 3: The mole concept is only used in chemistry.

Reality: The mole concept is used in many fields, including physics, biology, and engineering.

Conclusion

In conclusion, the mole concept and Avogadro's number are fundamental concepts in chemistry that are used to express the amount of substance in a sample. Understanding these concepts is crucial for understanding chemical reactions and stoichiometry. We hope that this Q&A article has provided further clarification on these important concepts.

Frequently Asked Questions

Q: What is the mole concept?

A: The mole concept is a unit of measurement that represents 6.022 x 10^23 particles of a substance.

Q: What is Avogadro's number?

A: Avogadro's number is a fundamental constant in chemistry that represents the number of particles in one mole of a substance.

Q: How do I calculate the number of moles in a sample?

A: To calculate the number of moles in a sample, you need to know the mass of the sample and the molecular weight of the substance.

References

IUPAC. (2019). Compendium of Chemical Terminology, 2nd ed. (the "Gold Book").
National Institute of Standards and Technology. (2020). Avogadro's Number.