6.1 The Mole Obj 1 a-c, 2 Chemistry

Essential Questions What is a mole and how is it used? What is formula mass? What is molar mass? How do you find molar/formula mass?

Measuring (don’t need to write) How do we measure eggs or milk? Why do you think there are different ways of counting something like eggs or paper? What unit of counting do you think chemists use when talking about atoms?

Avogadro's Number (don’t need to write) Named for Amadeo Avogadro 602213670000000000000000 or 6.02x1023

The Mole Chemists use the mole to count the number of particles or atoms. Chemists use the mole like bakers use a dozen. One mole equals 6.02 x 1023 particles (Avogadro's Number) The abbreviation for mole is mol

The Mole (cont) The mole is the same for all representative particles. Representative particle is a substance like atoms, molecules, or formula units. Molecule: two or more nonmetals (metalloids) Formula unit: metal and nonmetals Atom: single atom no subscripts

The Mole (cont) 1 mole NaCl= 6.02 x 1023 formula units NaCl 1 mole K = 6.02 x 1023 atoms K 1 mole H2O = 6.02 x 1023 molecules H2O

Mole (cont) Find the number of particles for the following: 1.05 mol NH3 Ans: 6.32x1023 molecules NH3 3.0 mol H2 Ans: 1.8x1024 molecules H2 0.768 mol NaCl Ans: 4.62 x1023 formula units NaCl 5.43x103 mol Cr Ans: 3.27x1027 atoms Cr

Mole (cont) Find the moles for the following 2.4 x 1023 formula units LiO Ans: 0.40 mol LiO 9.57 x 1021 molecules HCl 5.84 x 1025 atoms Na

Chemical Measurements Atoms have small mass (x10-23g) Special unit to measure atomic mass ATOMIC MASS UNIT (amu) Based on carbon-12 1 amu = 1/12 carbon-12 atoms mass Find the atomic mass of each atom Mass of O 15.999 amu Mass of Fe 55.847 amu Mass of C 12.011 amu

Mass of a Compound FORMULA MASS – sum of the atomic masses in a compound What is the mass of one molecule of water? H2O – 2 hydrogen atoms and 1 oxygen 2 (1.01 amu) + 1 (16.00 amu) = 18.02 amu Find the mass of C2H3O2 C: 2 atoms x 12.01 amu = 24.02 amu H: 3 atoms x 1.01 amu = 3.03 amu 0: 2 atoms x 16.00 amu = 32.00 amu Total = 59.05 amu Find the mass of Sr(NO3)2

Molar Mass Moles of different substances have different weights Mass of 1 mole of something = its MOLAR MASS Molar mass = atomic/formula mass in grams

Molar Mass (cont) Zinc Carbon dioxide Find the molar mass of Fe3(PO4)2 Atomic mass = 65.39 amu Molar mass = 65.39 g Carbon dioxide Formula mass = 44.00 amu Molar mass = 44.00 g Find the molar mass of Fe3(PO4)2

Essential Questions What is a mole and how is it used? What is formula mass? What is molar mass? How do you find molar/formula mass?

6.1 Tracked Assignment MUST SHOW WORK to receive credit on calculations P 296 #10-13,15 P 315 #48,50-54