Question

How many atoms are in a 3.56 g sample of Cu? Is this a mol of Cu?

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Answer 1

Answer:

3.37×10^22

Explanation:

N= n×NA

  = 3.56/63.5×NA

  = .056×(6.023×10^23)

   =3.37×10^22

Answer 2

Given: Given mass of Cu = 3.56g

To Find: Number of atoms of Cu

Step-by-step Explanation:

• Given mass of Cu = 3.56g
• Number of Cu moles can be calculated with the help of the following formula

• Number of Cu moles = $\frac{n}{N}$

• Here, n = given mass of Cu
• N = molecular weight of Cu
• As we know that the molecular weight of Cu is 63.5g.
• Number of moles of Cu = $\frac{3.56}{63.5}$ = $56$ × $10^{-3}$ moles.
• 1 mole = $6.023$ × $10^{23}$ atoms.
• Now, $56$ × $10^{-3}$ × $6.023$ × $10^{23}$ = $3.37$ × $10^{22}$ atoms.

Hence, the number of Cu atoms are $3.37$ × $10^{22}$ atoms.