An element is a substance that is made from one kind of atom only An element is a substance that is made from one kind of atom only. It cannot be broken down into simpler substances. atom atom An element An element

A compound is a substance that is made from more than one element. atom atom A compound made up of 2 different elements A compound made up of 7 different elements

A compound can be broken down into elements An element An element A compound made up of 3 different elements An element

Water Coal Carbon dioxide Oxygen Chalk Table salt Caffeine Material Made up of: Element or compound Water Hydrogen and Oxygen Coal Carbon Carbon dioxide Carbon and Oxygen Oxygen Chalk Calcium, Carbon & Oxygen Table salt Sodium & Chlorine Caffeine Carbon, Hydrogen, Nitrogen & Oxygen

What do all these have in common? They are made up of only 3 types of atoms: carbon, oxygen and hydrogen.

The chemical formula

Formula mass The formula mass of water (H2O) is 18 g.

What is the mass of 1 mole of methane (CH4)? Asked: The mass of 1 mole of methane Given: Methane (CH4) contains 1 carbon (C) and 4 hydrogen (H) atoms Relationships: The formula mass is the sum of the atomic masses for each atom in the compound Solve: Answer: One mole of methane (CH4) has a mass of 16.04 g.

How many moles are in 100 grams of water (H2O)? Asked: The moles in 100 g of water Given: Water (H2O) contains 2 hydrogen (H) atoms and 1 oxygen (O) atom. Relationships: The formula mass is the sum of the atomic masses for each atom in the compound. Solve: Answer: 100 g of water (H2O) contains 5.55 moles.

How many grams are in 2. 300 moles of butane (C4H10) How many grams are in 2.300 moles of butane (C4H10)? Butane is used as a lighter fluid in disposal lighter. Asked: The mass in grams of 2.300 moles of butane Given: 2.300 moles of C4H10 Relationships: The formula mass is the sum of the atomic masses for each atom in the compound. Solve: Answer: 133.7 g are in 2.300 moles of butane (C4H10).

Remember: How many oxygen atoms are in 200.0 g of glucose (C6H12O6)? Asked: Number of oxygen atoms Given: 200.0 g of C6H12O6 Relationships: Formula mass of glucose: Remember: Avogadro’s number indicates that one mole contains 6.02 x 1023 atoms

Solve: First we find how many moles are in 200.0 g of glucose: Next we find how many molecules are contained in 1.11 moles of glucose: Then we find how many O atoms are contained in 6.684 x 1023 molecules of glucose: Answer: There are 4.010 x 1024 atoms of O in 200.0 g of glucose (C6H12O6).

1 mol = Avogadro’s Number = 6.02 × 1023 units The Mole 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.

How Big Is a Mole? The volume occupied by one mole of softballs would be about the size of the Earth. One mole of Olympic shot put balls has about the same mass as the Earth.

Mole Calculations Steps: 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

Molar Mass The atomic mass of any substance expressed in grams is the molar mass (MM) of that substance. 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.

Calculating Molar Mass The molar mass of a substance is the sum of the molar masses of each element. 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.

6.02 × 1023 particles = 1 mol = molar mass Mole Calculations II Now we will use the molar mass of a compound to convert between grams of a substance and moles or particles of a substance. 6.02 × 1023 particles = 1 mol = molar mass If we want to convert particles to mass, we must first convert particles to moles and than we can convert moles to mass.

Mole Calculations II How many sodium atoms are in 0.120 mol Na? = 7.22 × 1022 atoms Na 0.120 mol Na × 1 mol Na 6.02 × 1023 atoms Na How many moles of potassium are in 1.25 × 1021 atoms K? = 2.08 × 10-3 mol K 1.25 × 1021 atoms K × 1 mol K 6.02 × 1023 atoms K

Mole Calculations II What is the mass of 2.55 × 1023 atoms of lead? 2.55 × 1023 atoms Pb × 1 mol Pb 6.02×1023 atoms Pb 207.2 g Pb 1 mole Pb × = 87.8 g Pb How many O2 molecules are present in 0.470 g of oxygen gas? 0.470 g O2 × 1 mol O2 32.00 g O2 6.02×1023 molecules O2 1 mole O2 × 8.84 × 1021 molecules O2

Mole Unit Factors We now have 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.

Mole-Volume- Mass Calculation A sample of methane, CH4, occupies 4.50 L at STP. How many moles of methane are present? 4.50 L CH4 × = 0.201 mol CH4 1 mol CH4 22.4 L CH4 What is the mass of 3.36 L of ozone gas, O3, at STP? 3.36 L O3 × × 22.4 L O3 1 mol O3 48.00 g O3 = 7.20 g O3

Molecule-Volume Calculation How many molecules of hydrogen gas, H2, occupy 0.500 L at STP? 0.500 L H2 × 1 mol H2 22.4 L H2 6.02×1023 molecules H2 1 mole H2 × = 1.34 × 1022 molecules H2

Chemical Formulas A particle composed of two or more nonmetal atoms is a molecule. A chemical formula expresses the number and types of atoms in a molecule. The chemical formula of sulfuric acid is H2SO4.

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.

Collection Terms 1 trio = 3 singers 1 six-pack Cola = 6 cans Cola drink 1 dozen donuts = 12 donuts 1 gross of pencils = 144 pencils

A Moles of Particles Contains 6.02 x 1023 particles 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

Examples of Moles Moles of elements 1 mole Mg = 6.02 x 1023 Mg atoms 1 mole Au = 6.02 x 1023 Au atoms Moles of compounds 1 mole NH3 = 6.02 x 1023 NH3 molecules 1 mole C9H8O4 = 6.02 x 1023 aspirin molecules

Avogadro’s Number 6.02 x 1023 particles 1 mole or 1 mole

Learning Check Suppose we invented a new collection unit called a mep. One mep contains 8 objects. A. How many paper clips in 1 mep? 1) 1 2) 4 3) 8 B. How many oranges in 2.0 meps? 1) 4 2) 8 3) 16 C. How many meps contain 40 gummy bears? 1) 5 2) 10 3) 20

Learning Check 1. Number of atoms in 0.500 mole of Al A) 500 Al atoms B) 6.02 x 1023 Al atoms C) 3.01 x 1023 Al atoms 2.Number of moles of S in 1.8 x 1024 S atoms A) 1.0 mole S atoms B) 3.0 mole S atoms C) 1.1 x 1048 mole S atoms

Solution 1. Number of atoms in 0.500 mol of Al C) 3.01 x 1023 Al atoms 0.500 mol Al x 6.02 x 1023 Al atoms 1 mol Al 2. Number of moles of S if a sample of S contains 4.50 x 1024 S atoms B) 3.0 mole S atoms 4.50 x 1024 S atoms x 1 mol S 6.02 x 1023 S atoms

Molar Mass Number of grams in 1 mole Equal to the numerical value of the atomic mass 1 mole of C atoms = 12.0 g 1 mole of Mg atoms = 24.3 g 1 mole of Cu atoms = 63.5 g

Learning Check Give the molar mass to 0.1 g A. 1 mole of Br atoms = ________ B. 1 mole of Sn atoms = ________

Molar Mass of Compounds Mass in grams of 1 mole equal numerically to the sum of the atomic masses 1 mole of CaCl2 = 111.1 g/mole 1 mole Ca x 40.1 g/mole + 2 moles Cl x 35.5 g/mole 1 mole of N2O4 = 74.0 g/mole 2 moles N x 14.0 g/mole + 4 moles O x 16.0 g/mole

Learning Check A. 1 mole of K2O = ______g B. 1 mole of antacid Al(OH)3 = ______g

Learning Check Prozac, C17H18F3NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of 1) 40.0 g/mole 2) 262 g/mole 3) 309 g/mole

Calculations with Molar Mass Grams Moles

Moles and Grams 3.00 moles Al ? g Al 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

Learning Check The artificial sweetener aspartame (Nutri-Sweet) formula C14H18N2O5 is used to sweeten diet foods, coffee and soft drinks. How many moles of aspartame are present in 225 g of aspartame?

Solution 1. Molar mass of Aspartame C14H18N2O5 (14 x 12.0) + (18 x 1.01) + (2 x 14.0) + (5 x 16.0) = 294 g/mole 2. Setup 225 g aspartame x 1 mole aspartame 294 g aspartame = 0.765 mole aspartame