5.3.1 The Mole Concept

• What is the fundamental unit in chemistry that measures the amount of a substance?

  Mole
• One mole contains 6.02
• Avogadro's constant is approximately 6.02 x 10²³ particles per mole.
• What formula is used to calculate the number of moles given the number of entities and Avogadro's constant?

  $n =$$\frac{N}{N_{A}}$
• In the formula $n =$$\frac{N}{N_{A}}$, $N_{A}$ represents Avogadro's
• What is the numerical value of Avogadro's number?

  $6.02 \times 10^{23}$
• Avogadro's number links the macroscopic amount of a substance to the number of microscopic entities
• Avogadro's number is a constant that relates the number of particles in a mole to the amount of the substance.
• What formula is used to calculate the number of particles in a given number of moles using Avogadro's number?

  $N =$$n \times N_{A}$
• Avogadro's number is equal to $6.022 \times 10^{23}$
• Molar mass is the mass of one mole of a substance expressed in grams per mole (g/mol).
• What formula is used to calculate the number of moles given the mass and molar mass of a substance?

  $n =$$\frac{m}{M}$
• The molar mass of a compound can be calculated by adding the atomic masses of all its elements
• Molar mass is typically expressed in grams per mole (g/mol).
• Steps to calculate the molar mass of a compound

  1️⃣ List each element in the compound.

  2️⃣ Find the atomic mass of each element from the periodic table.

  3️⃣ Multiply the atomic mass by the number of atoms of each element.

  4️⃣ Sum the resulting values to get the total molar mass.
• What is the SI unit for measuring the amount of a substance?

  Mole
• One mole contains $6.022 \times 10^{23}$ entities, which is Avogadro's constant.
• Avogadro's number links the macroscopic amount of a substance to the number of microscopic entities
• What formula is used to find the number of moles $(n)$ given the number of entities $(N)$?


  $n =$$\frac{N}{N_{A}}$
• In the formula $n =$$\frac{N}{N_{A}}$, $N$ represents the number of entities
• To find the number of moles in $1.8066 \times 10^{24}$ molecules of glucose, you would divide by Avogadro's number.
• What is the numerical value of Avogadro's number $(N_{A})$?


  $6.022 \times 10^{23}$
• Avogadro's number provides a link between the macroscopic amount of a substance and the number of microscopic entities
• What is the definition of molar mass $(M)$?


  Mass of one mole
• The formula to calculate moles from mass is $n =$$\frac{m}{M}$.
• What units is molar mass typically expressed in?

  $\text{g / mol}$
• The molar mass of NaOH is calculated as $22.99 +$$16.00 +$$1.01 =$$40.00 \text{ g / mol}$, resulting in 0.5 moles in 20 grams of NaOH.
• Steps to calculate the molar mass of a compound

  1️⃣ List each element in the compound

  2️⃣ Find the atomic mass of each element from the periodic table

  3️⃣ Multiply the atomic mass by the number of atoms

  4️⃣ Sum the resulting values
• What is the molar mass of H₂O (water)?

  18.016 \text{ g / mol}</latex>
• To convert mass to moles, use the formula $n =$$\frac{m}{M}$, where $M$ is the molar mass.
• To convert moles to mass, use the formula m = n \times M</latex>.
• How many moles are in 50 grams of NaCl (sodium chloride)?

  $0.856 \text{ moles}$
• The molar mass of H₂O is $18.016 \text{ g / mol}$, so 2 moles of H₂O have a mass of 36.032 grams.
• Balancing chemical equations requires determining the molar ratios of reactants and products.
• Steps to balance a chemical equation using molar ratios

  1️⃣ Write down the unbalanced equation

  2️⃣ Determine the molar ratios by balancing atoms

  3️⃣ Identify the moles of each substance
• In the balanced equation $2\text{H}_{2} +$$\text{O}_{2} \rightarrow 2\text{H}_{2}\text{O}$, how many moles of oxygen react with 2 moles of hydrogen?


  $1 \text{ mole}$