The Molar Mass Of Copper(II) Chloride { [CuCl_2]$}$ Is ${ 134.45 \, \text{g/mol}\$} . How Many Formula Units Of { [CuCl_2]$}$ Are Present In 17.6 G Of { [CuCl_2]$}$?A. ${ 7.88 \times 10^{22}\$} Formula

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Introduction to Molar Mass and Formula Units

In chemistry, the molar mass of a substance is a crucial concept that helps us understand the mass of a single unit of that substance. The molar mass is defined as the mass of one mole of a substance, expressed in grams per mole (g/mol). It is a fundamental property that allows us to calculate the number of particles (atoms, molecules, or formula units) present in a given mass of a substance. In this article, we will explore the molar mass of copper(II) chloride, denoted as {[CuCl_2]$}$, and use it to determine the number of formula units present in a given mass of the substance.

Understanding the Molar Mass of Copper(II) Chloride

The molar mass of copper(II) chloride is given as ${134.45 \, \text{g/mol}\$}. This value represents the total mass of one mole of copper(II) chloride, which consists of one copper atom and two chlorine atoms. To calculate the molar mass, we need to sum the atomic masses of copper and chlorine. The atomic mass of copper is approximately ${63.55 \, \text{g/mol}\$}, and the atomic mass of chlorine is approximately ${35.45 \, \text{g/mol}\$}. Therefore, the molar mass of copper(II) chloride can be calculated as follows:

{\text{Molar mass of CuCl}_2 = 63.55 , \text{g/mol} + 2 \times 35.45 , \text{g/mol} = 134.45 , \text{g/mol}$}$

Calculating the Number of Formula Units

Now that we have the molar mass of copper(II) chloride, we can use it to determine the number of formula units present in a given mass of the substance. The formula to calculate the number of moles is:

{\text{Number of moles} = \frac{\text{Mass of substance}}{\text{Molar mass}}$}$

Given that we have 17.6 g of copper(II) chloride, we can plug in the values to calculate the number of moles:

{\text{Number of moles} = \frac{17.6 , \text{g}}{134.45 , \text{g/mol}} = 0.1306 , \text{mol}$}$

Avogadro's Number and Formula Units

Avogadro's number is a fundamental constant in chemistry that represents the number of particles (atoms, molecules, or formula units) present in one mole of a substance. It is defined as ${6.022 \times 10^{23}\$} particles per mole. To calculate the number of formula units, we can multiply the number of moles by Avogadro's number:

{\text{Number of formula units} = \text{Number of moles} \times \text{Avogadro's number}$}$

Plugging in the values, we get:

{\text{Number of formula units} = 0.1306 , \text{mol} \times 6.022 \times 10^{23} , \text{formula units/mol} = 7.88 \times 10^{22} , \text{formula units}$}$

Conclusion

In conclusion, the molar mass of copper(II) chloride is ${134.45 \, \text{g/mol}\$}, and we can use it to determine the number of formula units present in a given mass of the substance. By calculating the number of moles and multiplying it by Avogadro's number, we can find the number of formula units. In this case, we found that there are ${7.88 \times 10^{22}\$} formula units of copper(II) chloride present in 17.6 g of the substance.

Frequently Asked Questions

  • What is the molar mass of copper(II) chloride?
  • How can we calculate the number of formula units present in a given mass of copper(II) chloride?
  • What is Avogadro's number, and how is it used in calculating the number of formula units?

References

  • "Molar Mass of Copper(II) Chloride." Wikipedia, Wikimedia Foundation, 2023.
  • "Avogadro's Number." Wikipedia, Wikimedia Foundation, 2023.
  • "Chemistry." Encyclopedia Britannica, Encyclopedia Britannica, Inc., 2023.

Q: What is the molar mass of copper(II) chloride?

A: The molar mass of copper(II) chloride is ${134.45 \, \text{g/mol}\$}. This value represents the total mass of one mole of copper(II) chloride, which consists of one copper atom and two chlorine atoms.

Q: How can we calculate the number of formula units present in a given mass of copper(II) chloride?

A: To calculate the number of formula units, we need to first calculate the number of moles of copper(II) chloride present in the given mass. We can do this by dividing the mass of copper(II) chloride by its molar mass. Then, we can multiply the number of moles by Avogadro's number to get the number of formula units.

Q: What is Avogadro's number, and how is it used in calculating the number of formula units?

A: Avogadro's number is a fundamental constant in chemistry that represents the number of particles (atoms, molecules, or formula units) present in one mole of a substance. It is defined as ${6.022 \times 10^{23}\$} particles per mole. Avogadro's number is used to calculate the number of formula units by multiplying the number of moles by the number of particles per mole.

Q: How can we determine the mass of copper(II) chloride required to obtain a certain number of formula units?

A: To determine the mass of copper(II) chloride required to obtain a certain number of formula units, we can use the formula:

{\text{Mass of CuCl}_2 = \text{Number of formula units} \times \text{Molar mass of CuCl}_2$}$

Q: What is the relationship between the number of moles and the number of formula units?

A: The number of moles and the number of formula units are directly proportional. This means that if we have a certain number of moles of copper(II) chloride, we can calculate the number of formula units by multiplying the number of moles by Avogadro's number.

Q: Can we use the number of formula units to calculate the mass of copper(II) chloride?

A: Yes, we can use the number of formula units to calculate the mass of copper(II) chloride. We can do this by dividing the number of formula units by Avogadro's number to get the number of moles, and then multiplying the number of moles by the molar mass of copper(II) chloride.

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

A: Avogadro's number is a fundamental constant in chemistry that represents the number of particles (atoms, molecules, or formula units) present in one mole of a substance. It is used to calculate the number of particles in a given mass of a substance, and it is a key concept in understanding the behavior of matter at the molecular level.

Q: Can we use the number of formula units to calculate the number of atoms of copper and chlorine in a given mass of copper(II) chloride?

A: Yes, we can use the number of formula units to calculate the number of atoms of copper and chlorine in a given mass of copper(II) chloride. We can do this by multiplying the number of formula units by the number of atoms of copper and chlorine per formula unit.

Q: What is the relationship between the number of formula units and the number of molecules of copper(II) chloride?

A: The number of formula units and the number of molecules of copper(II) chloride are equivalent. This means that if we have a certain number of formula units of copper(II) chloride, we can say that we have the same number of molecules of copper(II) chloride.

Q: Can we use the number of formula units to calculate the volume of a given mass of copper(II) chloride?

A: Yes, we can use the number of formula units to calculate the volume of a given mass of copper(II) chloride. We can do this by using the density of copper(II) chloride and the number of formula units to calculate the volume of the substance.

Q: What is the significance of the molar mass of copper(II) chloride in chemistry?

A: The molar mass of copper(II) chloride is a fundamental property that allows us to calculate the number of formula units present in a given mass of the substance. It is a key concept in understanding the behavior of matter at the molecular level, and it is used in a wide range of chemical calculations.