Honors Chemistry Unit 5 Mole/gram conversions

Mole Calculations: What are the steps in the Unit Analysis Method

-First we write down the unit asked for -Second we write down the given value -Third we apply unit factor(s) to convert the given units to the desired units

In Writing Chemical Formulas, If there is only one atom of a certain type, no ___is used.

1

Mole Unit Factors: What are the three interpretations for the mole?

1 mol = 6.02 × 1023 particles 1 mol = molar mass 1 mol = 22.4 L at STP for a gas This gives us 3 unit factors to use to convert between moles, particles, mass, and volume.

Moles and Grams: Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al? 3.00 moles Al ? g Al

1. Molar mass of Al 1 mole Al = 27.0 g Al 2. Conversion factors for Al 27.0g Al or 1 mol Al 1 mol Al 27.0 g Al 3. Setup 3.00 moles Al x 27.0 g Al 1 mole Al Answer = 81.0 g Al

1 miles of C atoms =

12.0g

1 mole of Mg atoms =

24.3g

1 mole C =

6.02 x 1023 C atoms

1 mole H2O =

6.02 x 1023 H2O molecules

1 mole NaCl =

6.02 x 1023 Na+ ions and 6.02 x 1023 Cl- ions

what is the numerical value of Avogadro's Number?

6.02 × 1023

A Mole of Particles contains? A mole is Avogadro's number of particles.

6.02 × 1023 particles.

1 mol = Avogadro's Number = ?

6.02 × 1023 units

1 mole of Cu atoms =

63.5g

What is a unit of measure for an amount of a chemical substance.

A mole (mol)

Avogadro's Number

Avogadro's Number (symbol N) is the number of atoms in 12.01 grams of carbon. Its numerical value is 6.02 × 1023. Therefore, a 12.01 g sample of carbon contains 6.02 × 1023 carbon atoms.

A molecule of the vitamin niacin has 6 carbon atoms, 6 hydrogen atoms, 2 nitrogen atoms, and 1 oxygen atom. What is the chemical formula?

C6H6N2O

The Law of Definite Composition states

Compounds always contain the same elements in a constant proportion by mass". EX:Sodium chloride is always 39.3% sodium and 60.7% chlorine by mass, no matter what its source. Water is always 11.2% hydrogen and 88.8% oxygen by mass.

If we want to ____________ particles to mass, we must first convert ___________ to _____________ and then we can convert moles to _________.

Convert, particles, moles, mass

Molar Mass Factors: Methane CH4 known as natural gas is used in gas cook tops and gas heaters. Express the molar mass of methane in the form of conversion factors.

Molar mass of CH4 = 16.0 g 16.0 g CH4 and 1 mole CH4 1 mole CH4 16.0 g CH4

Interpreting Chemical Formulas

Some chemical formulas use parenthesis to clarify atomic composition. Antifreeze has chemical formula C2H4(OH)2. There are 2 carbon atoms, 4 hydrogen atoms, and 2 OH units, giving a total of 6 hydrogen atoms and 2 oxygen atoms. Antifreeze has a total of 10 atoms.

Calculating Molar Mass

The molar mass of a substance is the sum of the molar masses of each element. EX: •What is the molar mass of magnesium nitrate, Mg(NO3)2? •The sum of the atomic masses is: 24.31 + 2(14.01 + 16.00 + 16.00 + 16.00) = 24.31 + 2(62.01) = 148.33 amu •The molar mass for Mg(NO3)2 is 148.33 g/mol.

Mass-Mole Calculations

What is the mass of 1.33 moles of titanium, Ti? We want grams, we have 1.33 moles of titanium. Use the molar mass of Ti: 1 mol Ti = 47.88 g Ti 1.33 mole Ti ×47.88 g Ti = 63.7 g Ti 1 mole Ti

A _______________ ______________ expresses the number and types of atoms in a molecule.

chemical formula EX: sulfuric acid formula is H2SO4

Some chemical formulas use parenthesis to clarify atomic _______________.

composition

The Mole (mol)

is a unit of measure for an amount of a chemical substance. A mole is Avogadro's number of particles, that is 6.02 × 1023 particles. 1 mol = Avogadro's Number = 6.02 × 1023 units We can use the mole relationship to convert between the number of particles and the mass of a substance.

The atomic mass of any substance expressed in grams is the _________ ___________of that substance.

molar mass (MM) EX: •The atomic mass of iron is 55.85 amu. •Therefore, the molar mass of iron is 55.85 g/mol. •Since oxygen occurs naturally as a diatomic, O2, the molar mass of oxygen gas is 2 times 16.00 g or 32.00 g/mol.

Now we will use the _______ _________of a compound to convert between _________ of a substance and _________ or particles of a substance.

molar mass, grams, moles EX: 6.02 × 1023 particles = 1 mol = molar mass

A particle composed of two or more nonmetal atoms is a __________.

molecule.

We can use the mole relationship to convert between the ___________________and the __________________________.

number of particles; the mass of a substance.

In Writing Chemical Formulas The number of each type of atom in a molecule is indicated with a ___________ in a chemical formula.

subscript

How Big Is a Mole? One mole of Olympic shot put balls has about the same mass as ______________.

the Earth.

How Big Is a Mole? The volume occupied by one mole of softballs would be about the size of ____________

the Earth.

Avogadro's Number (symbol N) is

the number of atoms in 12.01 grams of carbon.

The molar mass of a substance is?

the sum of the molar masses of each element.

What is the mass of 2.55 × 1023 atoms of lead?

•We want grams, we have atoms of lead. •Use Avogadro's number and the molar mass of Pb 2.55 × 1023 atoms Pb ×1 mol Pb 6.02×1023 atoms Pb X 207.2 g Pb 1 mole Pb = 87.8 g Pb