$$\text{g Cu} \rightarrow \text{mol Cu} \rightarrow \text{Number of Cu atoms}$$

$$3.10\ \text{g Cu} \times \frac{1\ \text{mol Cu}}{63.55\ \text{g Cu}} \times \frac{6.022 \times 10$$^{23}$$\ \text{Cu atoms}}{1\ \text{mol Cu}}$$

$$\text{Number of atoms} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \times 6.022 \times 10$$^{23}$$

$$2.107 \times 10$$^{-22}$$\ \text{g}$$

$$1\ \text{C atom} \rightarrow \text{mol C} \rightarrow \text{g C}$$

$$6.022 \times 10$$^{23}$$\ \text{atoms}/1\ \text{mol}$$

Question 1

Which of the following correctly describes the stepwise conversion from grams of copper to the number of copper atoms, as shown in the Pearson video?

Accepted Answer

$$	ext{g Cu} ightarrow 	ext{mol Cu} ightarrow 	ext{Number of Cu atoms}$$

Question 2

Given 3.10 g of copper, what is the correct sequence of conversion factors to find the number of copper atoms?

Accepted Answer

$$3.10\ 	ext{g Cu} 	imes \frac{1\ 	ext{mol Cu}}{63.55\ 	ext{g Cu}} 	imes \frac{6.022 	imes 10$$^{23}$$\ 	ext{Cu atoms}}{1\ 	ext{mol Cu}}$$

Question 3

What is the mass in grams of $$4.81 	imes 10$$^{22}$$ atoms of lead (Pb)? (Molar mass of Pb = 207.2 g/mol)

Accepted Answer

$$16.5\ 	ext{g}$$

Question 4

How many moles are in $$9.67\ 	ext{g} of $$gold (Au)? (Molar mass of Au = 196.967 g/mol)

Accepted Answer

$$0.0491\ 	ext{mol}$$

Question 5

Which of the following is the correct formula to calculate the number of atoms in a given mass of an element?

Accepted Answer

$$	ext{Number of atoms} = \frac{	ext{mass (g)}}{	ext{molar mass (g/mol)}} 	imes 6.022 	imes 10$$^{23}$$

Question 6

Calculate the mass of a single iodine atom ($$I) $$given its atomic mass is 126.90 g/mol.

Accepted Answer

$$2.107 	imes 10$$^{-22}$$\ 	ext{g}$$

Question 7

Which of the following best describes an ionic bond?

Accepted Answer

A bond resulting from the transfer of electrons from one atom to another, forming oppositely charged ions.

Question 8

Which of the following compounds would you expect to be a molecule rather than part of an ionic solid?

Accepted Answer

$$	ext{CO}_2$$

Question 9

A sample contains $$2.96 	imes 10$$^{22}$$ atoms of gold (Au). What is the mass of this sample in grams? (Molar mass of Au = 196.967 g/mol)

Accepted Answer

$$9.67\ 	ext{g}$$

Question 10

Which of the following is the correct conceptual plan for finding the mass of a single carbon atom?

Accepted Answer

$$1\ 	ext{C atom} ightarrow 	ext{mol C} ightarrow 	ext{g C}$$

Question 11

Which of the following statements about Avogadro's number is correct?

Accepted Answer

It is the number of particles in one mole of a substance, $$6.022 	imes 10$$^{23}$$.

Question 12

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two nonmetal atoms.

Question 13

If you have $$1.00 	imes 10$$^{24}$$ atoms of copper (Cu), what is the mass in grams? (Molar mass of Cu = 63.55 g/mol)

Accepted Answer

$$105.4\ 	ext{g}$$

Question 14

Which of the following is a correct conversion factor for converting from moles to atoms?

Accepted Answer

$$6.022 	imes 10$$^{23}$$\ 	ext{atoms}/1\ 	ext{mol}$$

Question 15

A student claims that $$1.00\ 	ext{g} of $$any element contains the same number of atoms. Is this correct?

Accepted Answer

No, because the number of atoms depends on the element's molar mass.

Study Guide: Mass, Moles, and Atoms in General Chemistry

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