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

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