Q: Which of the following is the correct formula to convert grams to moles?

$$\text{moles} = \frac{\text{given amount (g)}}{\text{molar mass (g/mol)}}$$

Question 1

Which of the following best defines a mole in chemistry?

Accepted Answer

The mass of a substance containing the same number of units as atoms in 12.0 g of Carbon-12.

Question 2

Which of the following compounds would NOT be associated with the term 'formula unit'?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$}$$

Question 3

Avogadro's number is fundamental in chemistry. What is its value?

Accepted Answer

$$6.022 	imes 10$$^{23}$$

Question 4

How many molecules are present in 0.5 moles of $$\mathrm{CO_2$}$$?

Accepted Answer

$$3.011 	imes 10$$^{23}$$

Question 5

A sample contains $$2.50 	imes 10$$^{24}$$ molecules of $$\mathrm{H_2O}$$. How many moles of water are present?

Accepted Answer

$$4.15 	imes 10$$^{0}$$ moles

Question 6

How many grams of $$\mathrm{O_2$}$$ contain $$9.25 	imes 10$$^{23}$$ molecules?

Accepted Answer

$$49.0 g$$

Question 7

If a sample of sodium chloride ($$\mathrm{NaCl}) $$contains $$71.1 g$$, what is its number of formula units?

Accepted Answer

$$6.12 	imes 10$$^{23}$$

Question 8

Calculate the number of oxygen atoms found in $$713 g of$$ $$\mathrm{Ni(NO_3$)_2 \cdot 6H_2O}.$$

Accepted Answer

$$2.314 	imes 10$$^{25}$$

Question 9

If the density of water is $$1.00 g/mL at$$ $$25^{\circ}C$$, calculate the number of water molecules found in $$1.50 	imes 10$$^{4}$$ $$\mu$$L of water.

Accepted Answer

$$5.01 	imes 10$$^{23}$$

Question 10

A cylindrical copper wire is used for the fuses around a house. The copper wire has a diameter of $$0.0750 in. $$How many copper atoms are found in its $$160 in $$piece? The density of copper is $$8.96 g/cm$^3.$$

Accepted Answer

$$6.56 	imes 10$$^{21}$$

Question 11

The density of the sun is $$1.41 g/cm$^3$$ and its volume is $$1.41 	imes 10$$^{27}$$ m^3$. How many hydrogen molecules are in the sun if we assume all the mass is hydrogen gas?

Accepted Answer

$$8.13 	imes 10$$^{57}$$

Question 12

Which of the following is the correct formula to convert grams to moles?

Accepted Answer

$$	ext{moles} = \frac{	ext{given amount (g)}}{	ext{molar mass (g/mol)}}$$

Question 13

How many moles of chlorine gas are there in $$3.01 	imes 10$$^{23}$$ molecules?

Accepted Answer

$$0.500$$ moles

Question 14

How many grams of chlorine gas are there in $$2.34$$ moles?

Accepted Answer

$$166.98 g$$

Question 15

Which of the following best describes the relationship between atoms, ions, molecules, and formula units in the context of the mole?

Accepted Answer

The mole serves as a bridge that connects the number of particles to the mass of a substance.

The Mole Concept: Chemical Composition and Quantities in Chemical Reactions

Guida di studio - Domande di pratica

Study guide - Flashcard