Question

 (Question) How many atoms are in 3 grams of Cu?
(20 points)

Answer 1

3 grams of Cu = 6.022 x 10^23 atoms of copper.

Answer 2

2.84 × 10^22 atoms

Step-by-step explanation:

To calculate the number of atoms in 3 grams of Cu, we can use avogadro's constant where:

`1 \: mole = 6.02 * 10 {}^(23) \: atoms`

Firstly, we have to calculate the number of moles in 3 grams of Cu. The formula to calculate moles is:

`moles = (mass)/(molar \: mass)`

the mass = 3g and the molar mass = 63.55 (this value can be found in the periodic table)

Substitute the values in formula:

`moles = (3)/(63.55)`

`moles = 0.0472`

Now use the number of moles to convert to atoms using avogadro's number, where x is the unknown number of atoms we want to find:

`1 \: mole : 6.02 * 10 {}^(23) \: atoms`

`0.0472 \: moles : x \: atoms`

Cross multiply and equate to solve for x:

`1 * x = 6.02 * 10 {}^(23) * 0.0472`

`x = 6.02 * 10 {}^(23) * 0.0472`

`x = 2.84 * 10 {}^(22) \: rounded \: to \: 3sf`

Hence, there are 2.84 × 10^22 atoms in 3 grams of Cu