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Mole
The mole, denoted as (mol), is the SI unit representing the amount of substance.
One mole
One mole is the amount of substance which contains the same number of particles as 12.0 g of Carbon-12.
Avogadro's number
Avogadro's number, also known as the Avogadro constant is the number of particles in one mole of any substance.
Avogadro's Number (NA)
NA = 6.022 x 1023
Molar Mass
The mass of one mole of substance is called the molar mass (or molecular weight). The unit of molar mass is g/mol.
Mole Ratio
A mole ratio is a conversion factor that relates the number of moles of different substances in a balanced chemical equation.
Conversion between mole and Avogadro's number
3 moles of HCl contain ................... HCl molecules.
Moles in atoms of Zinc
How many moles are in 3.01 x 1023 atoms of Zinc?
Molecules in water
How many molecules do 2.5 moles of water contain?
Moles of chlorine gas
How many moles of chlorine gas are there in 8.33 x 1023 molecules?
Molecules in carbon dioxide
How many molecules are in 0.25 mol of carbon dioxide?
Calculating Molar Mass
To find the molar mass of a compound, you need to sum the atomic masses of all the atoms in the compound, taking into account the number of each atom present.
Example of Molar Mass Calculation
Calculate molar mass of the following compounds: H₂O, Sodium Carbonate, Potassium Sulfate.
Stoichiometric relationship
It is a way to express the stoichiometric relationship between reactants and products in a reaction.
Coefficients in Mole Ratio
To determine the mole ratio, compare the coefficients of each of the substances in the equation.
Mole Ratio Example
The mole ratio of the above equation is 2 : 1 : 2.
Mole Ratio of Hydrogen to Water
What is the mole ratio of hydrogen gas to water in the following equation: H2 (g) + O2 (g) H2O (l)?
Avogadro's constant
The number of particles in one mole of a substance, approximately 6.022 x 10²³.
Chemical amount in moles
Calculated using the formula n = m / MM, where n is the amount in moles, m is mass in grams, and MM is molar mass in g/mol.
Percentage composition
The mass percentage of each element within a compound, calculated by dividing the mass of an element by the total mass of the compound and multiplying by 100.
Molecular formula
A formula that shows the actual number of each type of atom in a molecule.
Empirical formula
A formula that shows the simplest whole-number ratio of atoms in a compound.
Calculation of moles
The amount of substance n, in moles, can be calculated for a given mass of substance using the formula n = m / M.
Example of moles calculation
For 64g of oxygen (O2), n = 64 g / 32.0 g/mol = 2.0 mol O2.
Percentage composition of sodium carbonate
To determine, divide the mass of sodium by the total mass of sodium carbonate and multiply by 100.
Percentage composition of Hydrogen in water
Calculated by dividing the mass of Hydrogen in water by the total mass of water and multiplying by 100.
Example of empirical formula calculation
For a compound with 40% carbon, 6.7% hydrogen, and 53.3% oxygen, the empirical formula is CH2O.
Steps to calculate empirical formula
1. Convert mass percentages to grams. 2. Convert mass to moles. 3. Divide by the smallest number of moles. 4. Write the empirical formula.
Example of empirical formula from mass
A compound with 20.32 g of Carbon, 5.12 g of Hydrogen, and 7.9 g of Nitrogen needs to be analyzed to find its empirical formula.
Mass of sodium chloride
To find the mass of 0.2 mol of sodium chloride, multiply the number of moles by the molar mass of sodium chloride.
Finding moles of potassium bromide
Calculate the number of moles in 2.48 g of potassium bromide using the formula n = m / M.
Finding moles of carbonate
Calculate the number of moles in 6 kg of carbonate using the formula n = m / M.
Finding moles of hydrogen
Calculate the number of moles in 10 g of hydrogen using the formula n = m / M.
Diatomic molecule
A molecule composed of two atoms, such as O2.
Mass of glucose sample
To find the number of moles in a 1.52 kg sample of glucose C₆H₁₂O₆, convert kg to g and use the formula n = m / M.