Investigation 2: Weighing Toxins Lesson 5: Whack a mole!

Admit Slip Take a seat and quiet down for the Pop Quiz. © 2004 Key Curriculum Press. Unit IV • Investigation II-X

Today’s Objectives Students will be able to: Find the molar mass of an element or compound Convert a number of moles of a substance into its mass in grams Convert the mass of a substance into the number of moles. Find the number of atoms or molecules in a sample, given the mass. © 2004 Key Curriculum Press. Unit IV • Investigation II-X

Agenda Pop Quiz Admit Slip Quiz Review Exit Slip Product: Pop Quiz, Quiz Review, Exit Slip Homework: Study for Quiz Extra Credit Homework

Quiz Review Answers b) 6.02 x 1023 2. The mass of _one mole_ 3. a) Mg: 24.3 g/mol c) CaS: 72.1 g/mol b) CO2 : 44 g/mol d) C6H12O6:180 g/mol 4. 4 mol * 18 g/mol = 72 g   5. 2.3 mol * 25.8 g/mol = 68.5 g

Classwork Review 152 g / 54.94 g/mol = 2.76 mol 3.7 mol * 25 g/mol = 92.5 g 170 g / 32 g/mol = 5.3 mol 600 g / 98 g/mol = 6.1 mol 2.5 mol * 342 g/mol = 855 g

Classwork Review 400 g / 44 g/mol = 9.1 mol He = 4 g/mol 13. a) 2 B. 78 c) 72 d) 16 14. (PO4)2 is 8 O’s * 2 mol = 16 moles of O atoms

Classwork Review 15. 12 g Li 1.729 mol * 6.02 x 1023 = 10.40 x 1023 = 1.04 x 1024 atoms C / 6.94 g/mol = 1.729 moles (how many atoms are in 1 mole)

Classwork Review 16. 1.3 x 1025 molecules 1.3 x 1025 = 13 x 1024 = Hey, this kinda looks like the mole number. Let’s see if we can change it into 1023 1.3 x 1025 = 13 x 1024 = 130 x 1023 Let’s divide this by the mole number to see how many moles this is! 6.02 x 1023 = 21.59 moles = 22 mol B

Exit Slip / 28 g/mol = 5 moles How many N2 molecules are in a 140 g sample? 140 g N2 5 mol * 6.02 x 1023 = 30.1 x 1023 = 3.01 x 1024 molecules N2 / 28 g/mol = 5 moles (how many atoms are in 1 mole) © 2004 Key Curriculum Press. Unit IV • Investigation II-X

How are moles used to track chemical changes? •        Chemists use moles to track atoms and molecules that are going through chemical changes. •        Moles of atoms and molecules are conserved in a chemical equation. •        In order to calculate mass from moles: Multiply # of moles by the molar mass. •        In order to calculate moles from mass: Divide # of grams by the molar mass. © 2004 Key Curriculum Press. Unit IV • Investigation II-X