Homework 5 due today Wednesday 21 Feb Exam 1 Friday 23 Feb

What to expect on Exam 1: Prefixes and conversions between them Sig fig counting and computing Atomic parts and dimensions Average atomic masses Naming compounds Names/symbols of common elements (Know first 4 rows) Moles level 1,2 Hint for studying: See homework 1-5 and quiz 1 (answers at website)

1) Convert any mass or count to moles (divide up) Moles Level 2: `Body Parts’ Calculations- the Process 1) Convert any mass or count to moles (divide up) 2) Set up appropriate ratio with unknown mol quantity (m) and solve for m. 3) If necessary re-convert m to mass or count (multiply down)

how many moles of C6H12O6 can be made with 192 g of O ? Mole Body Part Calculations level 2: More practice, practice, practice 1)mole to mole: how many moles of O are present in 0.1666 mole of C6 H12O6? 1 mol O 2)weight to mole how many moles of C6H12O6 can be made with 192 g of O ? 2 moles C6H12O6

3) weight to moles how many moles of C6H12O6 in a sample containing 216 g C ? (at. wt of C=12 g/mol 18 0.333 3 6

Mole Calculations: part 2 (cont.) 4) moles to weight (MW how many grams of C6H12O6 (MW=180 g/mol) are formed with 0.2666 mol H? = 4 g

5) moles weight How many grams of C6H12O6 (MW=180 g/mol) contain 0 5) moles weight How many grams of C6H12O6 (MW=180 g/mol) contain 0.0333 mol C ? 1.00 g 0.05 g 0.4 g 0.00555 g

Mole Calculations: part 2 (cont.) 6) moles to atom count how many atoms of O are present in 0.8333 mol of C6 H12O6? =5*1023

7) Moles to atom count: how many atoms of C are in 0 7) Moles to atom count: how many atoms of C are in 0.02777 mol of C6H12O6? (1 mol =6*1023) 1.662*1022 1.3*1024 1.0*1023 1.0*1024

84 *1023 atoms of O 8 grams H 8) mass to molecules: Mole Calculations: part 2 (cont.) 8) mass to molecules: how many atoms of H in C6 H12O6 are combined with 84 g of C ? 84 *1023 atoms of O 8) atoms to mass: how many grams of H are combined with 2.4*1024 atoms of O in C6H12O 6 ? 8 grams H

9) mass molecules: How many molecules of C6H12O6 are present in a sample containing 32 g of O (at. wt=16 g/mol)? 1 1 mol count=6*1023 12*1023 5*1024 3.3*1023 2.0*1023

Mole Calculations: part 2 (cont.) 10) atoms to mass: how many grams of H are combined with 2.4*1024 atoms of O in C6H12O 6 ? 8 grams H

Prefixes and conversions between them Sig fig counting and computing Board examples of exam 1 problems for…. Prefixes and conversions between them Sig fig counting and computing Atomic parts and dimensions Average atomic masses Naming compounds Names/symbols of common elements (Know first 4 rows) Moles level 1,2