The Mole: A Measurement of Matter Chemical Quantities Chapter 10 Section 1

Vocabulary Mole Avogardro’s number The amount of a substance that contains 6.02 x 1023 representative particles of that substance. Avogardro’s number The number of representative particles contained in one mole of a substance; equal to 6.02 x 1023 particles.

Vocabulary Representative particles Molar Mass The smallest unit into which a substance can be broken down without a change in composition, usually atoms, molecules, or ions. Molar Mass A term used to refer to the mass of a mole of any substance.

State Standards 5.3 Use the mole concept to determine number of particles and molar mass for elements and compounds. 5.4 Determine percent compositions, empirical formulas, and molecular formulas.

Key Questions How can you convert among the court, mass, and volume of something? How do chemists count the number of atoms, molecules, or formula units in a substance? How do you determine the molar mass of an element and of a compound?

Measuring Mass Knowing how the count, mass, and volume of an item related to a common unit allows you to convert among these units.

What is a Mole? The mole allows chemists to count the number of representative particles in a substance. A mole is 6.02 x 1023 representative particles SI unit for measuring the amount of a substance Avogadro’s number is 6.02 x 1023

Molar Mass The atomic mass of an element expressed in grams is the mass of a mole of the element. The mass of a mole of an element is the molar mass.

The Mass of a Mole of a Compound To calculate the molar mass of a compound, find the number of grams of each element in one mole of the compound. Then add the masses of the element in the compound.

Assessment How many particles does one mole of any substance represent? 6.02 x 1023 representative particles of a substance How can you convert the number of atoms of any substance of moles? Multiply the number of atoms by the conversion factor 1 mole equals 6.02 x 1023 representative particles

Assessment What is the molar mass of Al2(CO3)3? Al C O 27 g/mol * 2 = 54 g/mol C 12 g/mol * 3 = 36 g/mol O 16 g/mol * 9 = 144 g/mol Total = 234 g/mol

Summary Knowing how to count, mass, and volume of an item relate to a common unit allows you to convert among these units. The mole allows chemists to count the number of representative particles in a substance. The atomic mass of an element expressed in grams is the mass of a mole of the element.

Summary To calculate the molar mass of a compound, find the number of grams of each element in one mole of the compound. Then add the masses of the elements in the compound.