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An element

atom. atom. An element is a substance that is made from one kind of atom only. It cannot be broken down into simpler substances. An element. An element. A compound is a substance that is made from more than one element. atom. atom. A compound made up of 7 different elements.

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An element

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

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

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

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

  5. The chemical formula

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

  7. 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.

  8. 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.

  9. 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).

  10. 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

  11. 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).

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 6.02 × 1023 atoms Na 1 mol K = 7.22 × 1022 atoms Na 0.120 mol Na × 1.25 × 1021 atoms K × = 2.08 × 10-3 mol K 1 mol Na 6.02 × 1023 atoms K Mole Calculations II • How many sodium atoms are in 0.120 mol Na? • How many moles of potassium are in 1.25 × 1021 atoms K?

  19. 1 mol Pb 207.2 g Pb 2.55 × 1023 atoms Pb × × 1 mol O2 6.02×1023 molecules O2 1 mole Pb 6.02×1023 atoms Pb 0.470 g O2 × × 1 mole O2 32.00 g O2 Mole Calculations II • What is the mass of 2.55 × 1023 atoms of lead? = 87.8 g Pb • How many O2 molecules are present in 0.470 g of oxygen gas? 8.84 × 1021 molecules O2

  20. 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.

  21. 1 mol O3 48.00 g O3 1 mol CH4 = 0.201 mol CH4 3.36 L O3 × × 4.50 L CH4 × 22.4 L O3 1 mol O3 22.4 L CH4 Mole-Volume- Mass Calculation • A sample of methane, CH4, occupies 4.50 L at STP. How many moles of methane are present? • What is the mass of 3.36 L of ozone gas, O3, at STP? = 7.20 g O3

  22. 1 mol H2 6.02×1023 molecules H2 × 0.500 L H2 × 22.4 L H2 1 mole H2 Molecule-Volume Calculation • How many molecules of hydrogen gas, H2, occupy 0.500 L at STP? = 1.34 × 1022 molecules H2

  23. 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.

  24. 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.

  25. 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

  26. A Moles of Particles Contains6.02 x 1023particles 1 mole C = 6.02 x 1023 C atoms 1 mole H2O = 6.02 x 1023H2O molecules 1 mole NaCl = 6.02 x 1023 Na+ ions and 6.02 x 1023Cl– ions

  27. 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 1023aspirin molecules

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

  29. 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

  30. 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 Alatoms 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

  31. Solution 1. Number of atoms in 0.500 mol of Al C) 3.01 x 1023 Alatoms 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

  32. 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

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

  34. 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

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

  36. 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

  37. Calculations with Molar Mass molar mass Grams Moles

  38. 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

  39. 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

  40. 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?

  41. 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

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