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

2. Unit IV Investigation II-X © 2004 Key Curriculum Press. Admit Slip Take out your homework to be checked!

3. Unit IV Investigation II-X © 2004 Key Curriculum Press. Todays 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.

4. Agenda Admit Slip Homework Review Mini Quiz Review Exit Slip Product: Mini Quiz Review, Exit Slip Homework: None

5. Homework Review 1.Find the molar masses of: a) Y 88.9 g/mol b) PH 3 34 g/mol c) (NH 4 ) 3 PO 4 42 + 12 + 31 + 64 = 149 g/mol 2. 4 mol * 28 g/mol = 112 g 3.3 mol * 60.1 g/mol = 180.3 g 4.4.2 mol * 132 g/mol = 554.4 g 2. What is the molar mass of nitrogen gas, N 2 ? What would be the mass of 5 moles of N 2 ? MM: 28 g/mol 5 mol: 140 g

6. Homework Review 5.126 g / 42 g/mol = 3 mol 6.850 g / 102 g/mol = 8.3 mol 7.920 g / 342 g/mol = 2.7 mol

7. Unit IV Investigation II-X © 2004 Key Curriculum Press. Exit Slip How many moles are in 185 g of F 2 ?

8. Unit IV Investigation II-X © 2004 Key Curriculum Press. 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.